bluuebunny/crossref_metadata_2025 huggingface dataset:
Three novel mutations in the ANK membrane protein cause craniometaphyseal dysplasia with variable conductive hearing loss
Authors: Kornak Uwe , Brancati Francesco , Le Merrer Martine , Lichtenbelt Klaske , Höhne Wolfgang , Tinschert Sigrid , Garaci Francesco Giuseppe , Dallapiccola Bruno , Nürnberg Peter
Published: March 2010

Craniometaphyseal dysplasia (CMD) is a rare, sclerosing skeletal disorder caused by mutations in ANKH, which encodes a putative pyrophosphate transporting membrane protein. Six distinct ANKH mutations have been described to date. We report here on three novel mutations in simplex patients with CMD. The c.1015T>C (p.Cys339Arg) mutation found in Patient A was associated with congenital facial palsy, early‐onset conductive hearing loss, and a generalized undermodeling of the long bones. The c.1172T>C (p.Leu391Pro) mutation in Patient B was associated with facial palsy, progressive conductive hearing loss, and generalized undermodeling of tubular bones. A milder phenotype without cranial nerve affection was observed in Patient C, associated with a c.1001T>G (p.Leu334Arg) mutation. All affected residues lie in evolutionarily conserved sequence blocks. These additional cases and the associated mutations contribute to an improved appreciation of the variability of this rare skeletal dysplasia. © 2010 Wiley‐Liss, Inc.
A second patient with Tsukahara syndrome: Type A1 brachydactyly, short stature, hearing loss, microcephaly, mental retardation and ptosis
Authors: Utine Gülen Eda , Breckpot Jeroen , Thienpont Bernard , Alanay Yasemin , Aksoy Cemalettin , Boduroğlu Koray , Devriendt Koenraad
Published: March 2010

In 1989, Tsukahara and colleagues described a single female with a provisionally unique pattern of malformation consisting of low intelligence, short stature, brachydactyly type A1, and characteristic facial features. We report on a second patient confirming Tsukahara syndrome as an established entity. © 2010 Wiley‐Liss, Inc.
Additional clinical and molecular analyses of TFAP2A in patients with the branchio‐oculo‐facial syndrome
Authors: Reiber Judith , Sznajer Yves , Posteguillo Elena Guillén , Müller Dietmar , Lyonnet Stanislas , Baumann Clarisse , Just Walter
Published: March 2010

The branchio‐oculo‐facial syndrome (BOFS) is a rare disorder with approximately 50 sporadic and familial cases in the literature. We report on the clinical and molecular analyses of five additional patients with BOFS (two familial and three sporadic). DNA analysis of the TFAP2A gene associated with BOFS using DNA sequencing detected a mutation [c.763A>G (p.Arg255Gly)] in two unrelated patients. This mutation had been reported in another patient and indicates a probable mutational hotspot in the TFAP2A gene. We also detected three new mutations which are restricted to exons 4–6. These gene regions are almost free of any single nucleotide polymorphisms. An evolutionary sequence comparison showed a high degree of sequence conservation from humans to the honey bee (Apis mellifera) in exon 6 showing that this part of the protein is probably essential. Our study represents the second group of BOFS patients with molecular confirmation, expanding the phenotype and spectrum of mutations and limiting it to a restricted part of the gene. © 2010 Wiley‐Liss, Inc.
Clinical variability of familial tumoral calcinosis caused by novel GALNT3 mutations
Authors: Ichikawa Shoji , Baujat Geneviève , Seyahi Aksel , Garoufali Anastasia G. , Imel Erik A. , Padgett Leah R. , Austin Anthony M. , Sorenson Andrea H. , Pejin Zagorka , Topouchian Vicken , Quartier Pierre , Cormier‐Daire Valerie , Dechaux Michele , Malandrinou Fotini Ch. , Singhellakis Panagiotis N. , Le Merrer Martine , Econs Michael J.
Published: March 2010

The GALNT3 gene encodes GalNAc‐T3, which prevents degradation of the phosphaturic hormone, fibroblast growth factor 23 (FGF23). Biallelic mutations in either GALNT3 or FGF23 result in hyperphosphatemic familial tumoral calcinosis or its variant, hyperostosis–hyperphosphatemia syndrome. Tumoral calcinosis is characterized by the presence of ectopic calcifications around major joints, whereas hyperostosis–hyperphosphatemia syndrome is characterized by recurrent long bone lesions with hyperostosis. Here we investigated four patients with hyperphosphatemia and clinical manifestations including tumoral calcinosis and/or hyperostosis–hyperphosphatemia syndrome to determine underlying genetic cause and delineate phenotypic heterogeneity of these disorders. Mutational analysis of FGF23 and GALNT3 in these patients revealed novel homozygous mutations in GALNT3. Although the presence of massive calcifications, cortical hyperostosis, or dental anomalies was not shared by all patients, all had persistent hyperphosphatemia. Three of the patients also had inappropriately normal 1,25‐dihyroxyvitamin D [1,25(OH)2D] and confirmed low circulating intact FGF23 concentrations. The four novel GALNT3 mutations invariably resulted in hyperphosphatemia as a result of low intact FGF23, but other clinical manifestations were variable. Therefore, tumoral calcinosis and hyperostosis–hyperphosphatemia syndrome represent a continuous spectrum of the same disease caused by increased phosphate levels, rather than two distinct disorders. © 2010 Wiley‐Liss, Inc.
A tale of two deletions: A report of two novel 20p13 → pter deletions
Authors: McGill Anna K. , Pastore Matthew T. , Herman Gail E. , Alliman Sarah , Rosenfeld Jill A. , Weaver David D.
Published: March 2010

We report on two patients with 1.7 and 1.2 Mb terminal 20p deletions, which have apparently not been reported previously. Both individuals exhibit certain similar features including large fontanelles, ear abnormalities, and seizures. However, even though the deletions are of similar size, there were many disparate features between the two. The deletions in each patient encompass at least 28 genes that may provide useful candidates for ear development and cranial ossification. © 2010 Wiley‐Liss, Inc.
Molecular and functional analysis of a novel MEK2 mutation in cardio‐facio‐cutaneous syndrome: Transmission through four generations
Authors: Rauen Katherine A. , Tidyman William E. , Estep Anne L. , Sampath Srirangan , Peltier Henry M. , Bale Sherri J. , Lacassie Yves
Published: March 2010

Cardio‐facio‐cutaneous (CFC) syndrome is one of the RASopathies and is caused by alteration of activity through the Ras/mitogen‐activated protein kinase (MAPK) pathway due to heterozygous de novo mutations in protein kinases BRAF, MEK1, or MEK2. CFC is a rare multiple congenital anomaly disorder in which individuals have characteristic dysmorphic features, cardiac defects, ectodermal anomalies and developmental delay. We report a $7{\raise0.5ex\hbox{$\scriptstyle 1$}\kern-0.1em/\kern-0.15em\lower0.25ex\hbox{$\scriptstyle 2$}}$‐month‐old boy with a clinical diagnosis of CFC. Bidirectional sequence analysis of MEK2 revealed a novel c.383C → A transversion in exon 3 resulting in a nonsynonymous missense substitution, p.P128Q. Other family members, including the proband's mother and half‐sibling, displayed phenotypic features of CFC and were also screened for the MEK2 mutation identified in the proband. Sorting Intolerant From Tolerant (SIFT) analysis determined the novel MEK2 p.P128Q to be deleterious. To corroborate the functional alteration of the novel mutant protein, transient transfection of HEK 293T cells with subsequent Western analysis was used to demonstrate increased kinase activity, as measured by ERK phosphorylation. This first reported case of a vertically transmitted functional CFC MEK mutation further expands our understanding of germline mutations within the Ras/MAPK pathway. © 2010 Wiley‐Liss, Inc.
Mutations and variants in the cohesion factor genes NIPBL, SMC1A, and SMC3 in a cohort of 30 unrelated patients with Cornelia de Lange syndrome
Authors: Pié Juan , Gil‐Rodríguez María Concepción , Ciero Milagros , López‐Viñas Eduardo , Ribate María Pilar , Arnedo María , Deardorff Matthew A. , Puisac Beatriz , Legarreta Jesús , de Karam Juan Carlos , Rubio Encarnación , Bueno Inés , Baldellou Antonio , Calvo Mª Teresa , Casals Nuria , Olivares José Luis , Losada Ana , Hegardt Fausto G. , Krantz Ian D. , Gómez‐Puertas Paulino , Ramos Feliciano J.
Published: March 2010

Cornelia de Lange syndrome (CdLS) manifests facial dysmorphic features, growth and cognitive impairment, and limb malformations. Mutations in three genes (NIPBL, SMC1A, and SMC3) of the cohesin complex and its regulators have been found in affected patients. Here, we present clinical and molecular characterization of 30 unrelated patients with CdLS. Eleven patients had mutations in NIPBL (37%) and three patients had mutations in SMC1A (10%), giving an overall rate of mutations of 47%. Several patients shared the same mutation in NIPBL (p.R827GfsX2) but had variable phenotypes, indicating the influence of modifiers in CdLS. Patients with NIPBL mutations had a more severe phenotype than those with mutations in SMC1A or those without identified mutations. However, a high incidence of palate defects was noted in patients with SMC1A mutations. In addition, we observed a similar phenotype in both male and female patients with SMC1A mutations. Finally, we report the first patient with an SMC1A mutation and the Sandifer complex. © 2010 Wiley‐Liss, Inc.
Fetal intracranial calcification: Pseudo‐TORCH phenotype and discussion of related phenotypes
Authors: Kulkarni Akhil Muralidhar , Baskar Shankar , Kulkarni Muralidhar Laxmanrao , Kulkarni Abhishek Jayateerth , Mahuli Amit Vasanth , Vittalrao Suhasini , Kulkarni Preethi Muralidar
Published: March 2010

Fetal intracranial calcification (ICC) noted during antenatal imaging poses a diagnostic challenge. Although this presentation is most commonly associated with intrauterine infection, non‐infectious causes of fetal ICC have been reported and include metabolic, genetic, or hemodynamic conditions. We report on a patient with antenatally detected extensive ICC, in whom postnatal imaging revealed a distinctive band‐like ICC with abnormal gyral pattern and a negative serology for TORCH infections. Such a constellation of findings have been previously described under the terminology of “pseudo‐TORCH phenotype,” and we posit that our patient represents this entity. Our patient had unreported dysmorphic features, which expands the phenotypic spectrum of this recently described heterogenous condition. In addition we report on the progression of the phenotype both clinically and radiologically. In view of the limited information available for the differential diagnosis of fetal ICC, we also review the available literature on this topic. © 2010 Wiley‐Liss, Inc.
Familial Aicardi–Goutières syndrome due to SAMHD1 mutations is associated with chronic arthropathy and contractures
Authors: Dale Russell C. , Gornall Hannah , Singh‐Grewal Davinder , Alcausin Melanie , Rice Gillian I. , Crow Yanick J.
Published: March 2010

We report on two siblings doubly heterozygous for null mutations in the recently identified AGS5 gene SAMHD1. The older female child showed mild intellectual disability with microcephaly. Her brother demonstrated a significant spastic paraparesis with normal intellect and head size. Both children had an unclassified chronic inflammatory skin condition with chilblains, and recurrent mouth ulcers. One child had a chronic progressive deforming arthropathy of the small and large joints, with secondary contractures. This family illustrate the remarkable phenotypic diversity accruing from mutations in genes associated with Aicardi–Goutières syndrome (AGS). The association of arthropathy with SAMHD1 mutations highlights a phenotypic overlap of AGS with familial autoinflammatory disorders such as chronic infantile neurological cutaneous and articular syndrome (CINCA). This family therefore illustrate the need to consider mutation analysis of SAMHD1 in non‐specific inflammatory phenotypes of childhood. We propose that arthropathy with progressive contractures should now be considered part of the spectrum of Aicardi–Goutières syndrome because of SAMHD1 mutations. © 2010 Wiley‐Liss, Inc.
New subtype of familial intracranial calcification in a mother and two children
Authors: Elsaid Mahmoud F. , Crow Yanick J. , Livingston John H. , Ben‐Omran Tawfeg
Published: March 2010

We report on a mother and two children from a consanguineous Arab Qatari family demonstrating a highly distinctive pattern of intracranial calcification involving the globus pallidus, posterior limb of the internal capsule, genu of the corpus callosum, and deep white matter. Both siblings, a girl and boy, presented with neonatal seizures without subsequent deterioration in neurological function. The girl demonstrated mild to moderate psychomotor delay but her brother and mother showed completely normal development. All three affected individuals were normocephalic. To the best of our knowledge this phenotype represents a novel disorder of inherited brain calcification, which may be recognizable on computerized tomography brain imaging in other cases. Although the disease shows apparent autosomal dominant inheritance, the high degree of consanguinity in the family leaves open the possibility of pseudo‐dominance for an autosomal recessive trait. © 2010 Wiley‐Liss, Inc.
Flocculation of reed pulp suspensions by quaternary chitosan‐nanoparticle SiO2retention aid systems
Authors: Zhang Xiaohui , Gu Wen Juan , Li Houbin , Chi Huang , Chen Lingyun
Published: March 2010

The microparticle retention aid system has been a focus on the studies of paper‐making chemicals.N‐(2‐Hydroxy‐3‐trimethylammonio)‐propyl chitosan chlorider [quaternary chitosan (QCS)]—nanoparticle SiO2dual component system was investigated in this work. The adsorpton kinetic experiments indicated that there was a very fast (<1 min) polymer adsorption under good mixing conditions. Adsorption of QCS onto the fiber surface was followed by a rearrangement to reach an equilibrium conformation. At the same time, QCS chains, existing on the surface of fiber, could permeate into the porous of the fiber, resulting in the reducing of zeta potential of the cellulosic fiber. In addition, the flocculation would be increased with the increasing of SiO2when the fiber substrates surfaces was net positively charged by an adsorbed QCS layer. It was also found that ionic strength decreased significantly the flocculation efficiency in pure QCS system, whereas the turbidity of the reed pulp suspension increased slightly with the increasing of NaCl concentration in QCS‐SiO2systems. The effect of shear force on the flocculation was tested. It was shown shear led to floc breakage and decreased the flocculation. These phenomena were very obvious for one‐component system (QCS or C‐St), but the microparticle system (QCS‐SiO2or C‐St‐SiO2) was shear resistance. Dynamic drainage experiment indicated that the turbidity of white water was decreased with the increasing of dosage of SiO2in experimental level. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Synthesis and thermal characterization of random poly(butylene terephthalate‐co‐2‐methyl‐ethylene terephthalate) copolyesters
Authors: Wu Fangjuan , Yang Guisheng
Published: March 2010

Poly(butylene terephthalate‐co‐2‐methyl‐ethylene terephthalate) (PBT/MET) was synthesized by incorporating 1,2‐propandiol(1,2‐PDO) into PBT chains. The molar composition and chemical structure of PBT/MET copolyesters were confirmed by means of FT‐IR and 1H‐NMR. To investigate the effect of 1,2‐PDO on the thermal properties of PBT/MET copolyesters, the copolymerizations were carried out by varying various contents of MET units, and the prepared materials were evaluated by differential scanning calorimetry and thermogravimetric analysis. Results suggested that with the increase of the content of 1,2‐PDO, the amount of crystallinity and the melting temperature decline, while the glass transition temperature increases and the copolyesters become more transparent and brittle with respect to PBT homopolymer. In addition, the Tg‐composition and Tm‐composition data are well subjected to the Wood equation and Flory's equation, respectively. All these copolyesters are found to consist of the general trend displayed by copolymers reported elsewhere. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Elaboration of superparamagnetic cobalt–ferrite nanocomposites from films of chitosan chelates
Authors: Garza‐Navarro M. A. , González‐González V. A. , Torres‐Castro A. , Hinojosa M. , García‐Loera A. , José‐Yacamán M.
Published: March 2010

Cobalt–ferrite nanocomposites were synthesized from polymeric films of chelates of Co(II) and Fe(III) ions within a chitosan matrix by a solid‐state coprecipitation reaction with weight content ratios of chitosan to cobalt–ferrite of 50/50 and 25/75 w/w. Morphological and crystalline studies of the composites were performed by high‐resolution transmission electron microscopy, X‐ray diffraction, and selected area electron diffraction with a nanobeam diffraction probe. The results show nanoparticles around 4 nm with a spinel structure, consistent with the cobalt–ferrite phase. The magnetic behavior was evaluated with curves of the applied‐field‐dependent magnetization [M(H)] and the temperature‐dependent magnetization [M(T)]. Both theM(H) andM(T) curves showed typical superparamagnetic behavior, depicting an absence of hysteretic characteristics and the characteristic peak at blocking temperature in the zero‐field‐cooled curve. There was also evidence of strong interparticle and intraparticle interactions, which suggested magnetic frustration in the particle magnetic moment alignment with the applied field. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Novel comb‐structured‐polymer‐grafted carbon black by surface‐initiated atom transfer radical polymerization and ring‐opening polymerization
Authors: Yang Qiang , Wang Li , Huo Jia , Ding Jianhua , Xiang Weidong
Published: March 2010

Novel comb‐structured‐polymer‐grafted carbon black (CB) was synthesized with a combination of surface‐initiated atom transfer radical polymerization and ring‐opening polymerization. First, poly(2‐hydroxyethyl methacrylate) (PHEMA) was grafted onto the CB surface by surface‐initiated atom transfer radical polymerization. The prepared CB‐g‐PHEMA contained 35.6–71.8% PHEMA, with the percentage depending on the molar ratio of the reagents and the reaction temperature. Then, with PHEMA in CB‐g‐PHEMA as the macroinitiator, poly(ϵ‐caprolactone) (PCL) was grown from the CB‐g‐PHEMA surface by ring‐opening polymerization in the presence of stannous octoate. CB‐g‐PHEMA and CB‐g‐(PHEMA‐g‐PCL) were characterized with Fourier transform infrared, 1H‐NMR, thermogravimetric analysis, dynamic light scattering, and transmission electron microscopy. The resultant grafted CB had a shell of PHEMA‐g‐PCL. On the whole, the CB nanoparticles were oriented in dendritic lamellae formed by these shells. This hopefully will result in applications in gas sensor materials and nanoparticle patterns. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Swelling characteristics of poly(N‐isopropylmethacrylamide‐co‐itaconic acid) gels prepared in various conditions
Authors: Vakıflı Ayşe , Demirel Gökçen Birlik , Caykara Tuncer
Published: March 2010

Thermo‐ and pH‐sensitive gels composed of N‐isopropylmethacrylamide (NIPMA) and itaconic acid (IA) were prepared by free‐radical crosslinking copolymerization in poly(ethylene glycol) (PEG) solution at 22°C and in water at −22°C and at 22°C, which were called as the macroporous gel (MGel), the cryogel (CGel), and the conventional gel (NGel), respectively. The gels were characterized by the equilibrium swelling, interior morphology, and deswelling kinetics. With increasing temperature in water, the gels exhibit reentrant conformational phase transition. During this transition, the gels first deswell in the range of temperature between 5 and 29°C, then drastically reswell if temperature is monotonically increased. The reswelling of the collapsed gels occurs above 45°C. It was shown that the reentrant transition in poly(N‐isopropylmethacrylamide‐co‐itaconic acid) [poly(NIPMA‐co‐IA)] gels requires moderate temperature, so that the hydrophobic interactions between chains dominate the swelling process. Scanning electron micrographs revealed that the interior network structure of MGel is more porous compared with those of CGel and NGel. This more porous structure provided numerous water channels for water diffusion out of the matrix and, therefore, an improved response rate to the external temperature and pH changes during the deswelling process. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Miscibility, crystallization kinetics, and mechanical properties of poly(3‐hydroxybutyrate‐co‐3‐hydroxyvalerate)(PHBV)/poly(3‐hydroxybutyrate‐co‐4‐hydroxybutyrate)(P3/4HB) blends
Authors: Wang Xiaojuan , Chen Zhifei , Chen Xianyu , Pan Jueyu , Xu Kaitian
Published: March 2010

Poly(3‐hydroxybutyrate‐co‐3‐hydroxyvalerate)(PHBV)/poly(3‐hydroxybutyrate‐co‐4‐hydroxybutyrate) (P3/4HB) blend films were prepared by solvent‐cast method. The nonisothermal crystallization results showed that PHBV and P3/4HB are miscible due to a single glass transition temperature (Tg), which is dependent on blend composition. The isothermal crystallization results demonstrate that the crystallization rate of PHBV becomes slower after adding amorphous P3/4HB with 19.2 mol% 4HB, which could be proved through depression of equilibrium melt point ($T_m^o$) from 183.7°C to 177.6°C. For pure PHBV and PHBV/P3/4HB (80/20) blend, the maximum crystallization rate appeared at 88°C and 84°C, respectively. FTIR analysis showed that PHBV/P3/4HB blend films would maintain the helical structure, similar to pure PHBV. Meanwhile, with increasing P3/4HB content, the inter‐ and intra‐interactions of PHBV and P3/4HB decrease gradually. Besides, a lower elastic modulus and a higher elongation at break were obtained, which show that the addition of P3/4HB would make the brittle PHBV to ductile materials. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Mechanical properties of poly(ether ether ketone)/poly(ether ketone) blends: Use of simple models relating normalized tensile parameters
Authors: Mandal Subhash , Alam Sarfaraz
Published: March 2010

In this study, mechanical properties such as tensile properties, flexural properties, and Izod impact strength of poly(ether ether ketone) (PEEK) and poly(ether ketone) (PEK) blends at PEK concentration from 0 to 0.42 volume fraction were studied. The blends of PEEK and PEK of different compositions were prepared by extrusion in a single‐screw extruder. With increase in the PEK concentrations, the tensile strength, flexural strength, and modulus increased whereas the tensile modulus and the impact strength decreased. Homogeneous dispersion and adhesion of PEK in PEEK was shown by the morphological studies. Crystallinity of blends influenced the tensile modulus and the impact strength. Using simple models to relate normalized tensile parameters where the data were divided by the crystallinity of the blends and of the PEEK matrix, respectively, supported the experimental results. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Structure and antimicrobial activity relationship of quaternary N‐alkyl chitosan derivatives against some plant pathogens
Authors: Badawy Mohamed E. I.
Published: March 2010

In the present work, quaternary chitosans as water‐soluble compounds were prepared based on three‐step process. Schiff bases were firstly synthesized by the reaction between the amino groups of chitosan with aliphatic aldehydes followed by a reduction with sodium borohydride (NaBH4) to form N‐(alkyl) chitosans. N,N,N‐(dimethyl alkyl) chitosans were then obtained by a reaction of chitosan containing N‐butyl, N‐pentyl, N‐hexyl, N‐heptyl, and N‐octyl substituents with methyl iodide. The compounds were characterized using IR and NMR spectroscopy. Subsequent experiments were conducted to test their antimicrobial activities against the most economic plant pathogenic bacteria of crown gall disease Agrobacterium tumefaciens, soft mold disease Erwinia carotovora, fungi of grey mold Botrytis cinerea, root rot disease Fusarium oxysporum, and damping off disease Pythium debaryanum. Quaternary chitosans enhanced the antibacterial activity and N,N,N‐(dimethyl pentyl) chitosan was the most active one with Minimum Inhibitory Concentration (MIC) of 750 and 1225 mg/L against A. tumefaciens and E. carotovora, respectively. All quaternized chitosans gave stronger antifungal activities than chitosan where N,N,N‐(dimethyl pentyl) chitosan and N,N,N‐(dimethyl octyl) chitosan were significantly the highest in mycelial growth inhibiation against B. cinerea (EC50 = 908 and 383 mg/L, respectively), F. oxysporum (EC50 = 871 and 812 mg/L, respectively), and P. debaryanum (EC50 = 624 and 440 mg/L, respectively). In addition, spore germination of B. cinerea and F. oxysporum was significantly affected with the compounds at the tested concentrations and the inhibition activity was increased with an increase in the chain length of the alkyl substituent. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Synthesis and characterization of polypyrrole dodecylbenzenesulfonate‐titanium dioxide nanocomposites
Authors: Shakoor Abdul , Rizvi Tasneem Zahra
Published: March 2010

Nanocomposites of polypyrrole dodecylbenzenesulfonate‐titanium dioxide have been prepared from a colloidal solution of titanium dioxide (TiO2) nanoparticles. The DC conductivity of samples with different concentrations of TiO2 has been investigated under dark and light. The doping effect of TiO2 has been characterized and evaluated by transmission electron microscopy (TEM), Fourier transform infrared spectroscopy, and X‐ray diffraction. TEM shows that TiO2 nanoparticles have strong effects on the morphology of composites, and conductivity measurements show that the conductivity first increases and then decreases as the percentage of TiO2 is increased in the composites exhibiting a maximum in conductivity at about 20 wt % of TiO2. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Telechelic siloxanes with hydrogen‐bonded polymerizable end‐groups. II. IR studies of end‐groups interactions—Model amides and ureas
Authors: Mazurek M. , Leir C. M. , Galkiewicz R. K.
Published: March 2010

Hydrogen‐bonding phenomena in amides and ureas are of great practical and theoretical importance. In this article, we report on infrared temperature studies aimed at the elucidation of the hydrogen‐bonding phenomena of (meth)acrylamide groups directly linked to the alkyl groups of telechelic polydimethylsiloxane (PDMS) which serve as models of monoamides, or linked to the alkyl groups of telechelic PDMS through amide spacers‐models of diamides (dipeptides). Similarly, we have examined the hydrogen‐bonding phenomena in urea‐terminated telechelic PDMSs to which free‐radically polymerizable groups (methacrylate, α‐methylstyryl) are attached. Hydrogen bonding in the derivatives of these substituted silicone amides and ureas in the unreacted (liquid) state has been studied, as well as in films formed via ultraviolet‐initiated free‐radical polymerization of those reactive end‐groups. The extreme flexibility of the silicones provides a medium in which polar, hydrogen‐bonding end‐groups (amides, diamides, and ureas) phase‐separate to form their own domains wherein they can freely aggregate in an essentially unperturbed state, when in the liquid form. When the vinyl end‐groups are polymerized, interactions between the hydrogen bonding groups attached to them can be studied in a spatially constrained environment. High thermal stability of the silicones allows the study of the hydrogen bonding (H‐bonding) phenomena of these models within a broad temperature range. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Preparation and physico‐mechanical, thermal and acoustic properties of flexible polyurethane foams based on hydroxytelechelic natural rubber
Authors: Saetung Anuwat , Rungvichaniwat Adisai , Campistron Irène , Klinpituksa Pairote , Laguerre Albert , Phinyocheep Pranee , Doutres Olivier , Pilard Jean‐François
Published: March 2010

Novel flexible polyurethane foams were successfully prepared from a renewable source, hydroxytelechelic natural rubber (HTNR) having different molecular weights (1000–3400 g mol−1) and variation of epoxide contents (EHTNR, 0–35% epoxidation) by a one‐shot technique. The chemical and cell structures as well as physico‐mechanical, thermal, and acoustic properties were characterized and compared with commercial polyol analogs. The obtained HTNR based foams are open cell structures with cell dimensions between 0.38 and 0.47 mm. The HTNR1000 based foam exhibits better mechanical properties but lower elongation at break than those of commercial polyol analog. However, the HTNR3400 based foam shows the best elastic properties. In a series of EHTNR based foams, the tensile and compressive strengths show a tendency to increase with increasing epoxide content and amount of 1,4‐butanediol (BD). The HTNR based foams demonstrate better low temperature flexibility than that of the foam based on commercial polyol. Moreover, the HTNR based polyurethane foams was found to be an excellent absorber of acoustics. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Effect of the structure at the micrometer and nanometer scales on the light transmission of isotactic polypropylene
Authors: Zia Qamer , Androsch René , Radusch Hans‐Joachim
Published: March 2010

The spherulitic superstructure, crystallinity, and structure and morphology of crystals of isotactic polypropylene were controlled by the conditions of melt crystallization and related to the transmittance of visible light. Spherulitic samples, which contained monoclinic lamellae, were prepared by slow cooling of the quiescent melt at rates lower than 10 K/s and by isothermal melt crystallization at temperatures between 373 and 413 K. Nonspherulitic specimens, which contained nonlamellar mesomorphic domains, in contrast, were obtained by rapid cooling of the melt with rates faster than 100 K/s. The crystallinity and the size of crystals were furthermore fine‐tuned by subsequent annealing at elevated temperatures. Analysis of such films of different structure by ultraviolet–visible spectroscopy revealed that the light transmission was independent of (1) the fraction, (2) the internal structure, and (3) the size of the crystals. In contrast, the light transmission increased with decreasing size of spherulites and finally exceeded 90% in films of 100 μm thickness when spherulites were completely absent. The crystallinity and the structure and size of the crystals of the films of isotactic polypropylene could be adjusted within wide limits without affecting the light transmission. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Aspects of network formation in glassy thermosets
Authors: Detwiler Andrew T. , Lesser Alan J.
Published: March 2010

Aspects of network formation and the physical properties of stoichiometric amine‐cured epoxy resins are investigated. The state of network formation is systematically controlled by using isothermal cure conditions and a linear temperature ramp condition. Affine deformation in compression at a constant true strain rate is used to measure the true stress–strain response from small strains to large strains. Beginning with the low‐strain responses and continuing through yielding, partially cured samples demonstrate characteristics of physical ageing that diminish as the networks approach full conversion. The postyield properties are characterized by a strong dependence on network connectivity with little influence of the curing method. The mechanical responses are also applied to necking and shear banding analyses. The resins are unable to achieve stable necking in tension. However, shear bands are able to be stabilized, as predicted by a model developed in this work. These results suggest that physical ageing is inherent in epoxy network formation, and the resulting strain localization significantly degrades the mechanical integrity of epoxy resins in the partially cured state, regardless of the cure conditions. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Measurement of the pressure dependence of viscosity of polymer melts using a back pressure‐regulated capillary rheometer
Authors: Aho Johanna , Syrjälä Seppo
Published: March 2010

The effect of pressure on the melt viscosity was experimentally investigated for five polymers: polycarbonate (PC), acrylonitrile‐butadiene‐styrene (ABS), polystyrene (PS), polypropylene (PP), and low‐density polyethylene (LDPE). Measurements were carried out using capillary rheometer modified to allow regulation of back pressure. To enable correction for the entrance pressure drop, two round‐hole dies were used: a 1‐mm diameter die of length 10 mm and an orifice die of the same diameter. For determining the pressure coefficient from the experimental viscosity data, time‐pressure superposition was applied to generate a master curve to which the Carreau‐Yasuda model was fitted. The resulting pressure coefficients revealed that for the polymers studied the order of the degree of the pressure dependence is as follows: PS > ABS > PC > PP > LDPE. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Hybrid organic/inorganic dendritic triblock copolymers: Synthesis, nanostructure characterization, and micellar behavior
Authors: Namazi Hassan , Jafarirad Saeed
Published: March 2010

A new class of amphiphilic dendritic ABA triblock copolymers, which is based on organic linear polyethylene oxide (PEO) and inorganic dendritic carbosiloxane (CSO) was synthesized. The strategy used in synthesizing these materials is based on divergent method using hydrosilylation‐alcoholysis cycles. The reaction conditions and structural features of dendrimers were analyzed by different physicochemical techniques such as: GPC, NMR, UV spectroscopy, DSC, and viscometry. The generational limit of dendrimer after the first generation, OSC‐D‐PEO‐D‐CSO, forced us to employ HSiCl2CH3 as branching reagent. Also further hydrosilylation of the third generation yielded an irregular structure species. Self‐assembling and morphological studies of first, OSC‐D‐PEO‐D‐CSO, and second, OSC‐D‐PEO‐D‐CSO, generations in aqueous medium were monitored by using fluorescence, TEM and DLS techniques. However, the dendritic block copolymer with third generation, OSC‐D‐PEO‐D‐CSO, could not be dispersed in aqueous phase. The diameters of denderitic micelles had a narrow distribution in the ranges of 69 and 88 nm, respectively. Although the micelles were stable even in first generation, partition equilibrium constants of pyrene and critical micelle concentration in both of dendritic micelles imply that the micellar behaviors of the supramolecules strongly depend on the hydrophobic block's size in which increasing generation effectively promoted the micelle formation. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Solubility profiles of poly(ethylene glycol)/solvent systems. II. comparison of thermodynamic parameters from viscosity measurements
Authors: Di̇nç Cemile Özdemir , Ki̇barer Günay , Güner Ali
Published: March 2010

Solution thermodynamics of PEG samples in aqueous and nonaqueous (methanol, chloroform, tetrahydrofuran, and dimethylsulfoxide) solutions have been investigated by viscometric studies at 25, 30, 35, and 40°C. The hydrodynamic expansion factor, ah, and the unperturbed root mean square end‐to‐end distance, $ \langle r^{2}\rangle_\theta^{1/2} $, found for the system indicated that the polymer coils contract as the temperature is raised. The long‐range interaction parameter, B, was also evaluated and a significant decrease with increasing temperature was observed. The theta temperatures, θ, obtained from the temperature dependence of (1/2 − χ) and the second virial coefficient, A2, are quite good in agreement with the calculated values evaluated via extrapolation and interpolation methods. The thermodynamic interaction parameter, χ, was evaluated through the sum of the individual values of enthalpy and entropy dilution parameters for PEG samples. The restrictions applying to the establishment of concentration regimes, short‐range, and long‐range interactions are discussed. A parallelism is found between solubility profiles obtained by solution viscometry and solubility parameter approaches for PEG/solvent systems. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Extraordinary swelling behavior of poly(AMPS) organogel in solvent/DMSO binary mixed media
Authors: Zohuriaan‐Mehr M. J. , Kabiri K. , Kheirabadi M.
Published: March 2010

The present article deals with super‐swelling behavior of crosslinked homopolymer of 2‐acrylamido‐2‐methylpropane sulfonic acid, poly(AMPS), in binary mixtures of dimethyl sulfoxide (DMSO) and various polar solvents including water, mono‐, and polyhydric alcohols, and amide solvents such as N‐methyl pyrrolidone. Extraordinary phase transition sequences including a new unusual swelling phenomenon, referred to as “overentrant” swelling, was observed for this polymeric organogel in the solvent/DMSO mixtures. The swelling behaviors were preliminarily explained based on the major interactions involved in the solvation process and dielectric constant of the swelling media. It was established that the “overentrant” region of the swelling profiles was progressed with the increase of dielectric constant of the mixed solvent media. The overentrant region was disappeared with partial replacement of AMPS units with acrylic acid. This was taken as an additional practical evidence for a major role of the sulfonic acid as the main interactive group involved in the solvation process. The unusual phase transitions were also explained via a semiquantitative approach based on the Gutmann's acceptor number and donor number values to emphasis on the key effect of dissociation degree of the sulfonic acid group (as a function of the solvent type and composition) on the swelling behaviors. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Surface properties of lithospermum‐containing multiple phase emulsion systems
Authors: Tsai Chi , Lin Li‐Huei , Wu Chin‐Sheng , Kwan Chang‐Chin
Published: March 2010

In this study, we employed a one‐step emulsion process—rather than the traditional, relatively difficult two‐step process—to obtain multiple phase emulsion systems containing the Chinese herbal medicine lithospermum. We characterized these systems in terms of their contact angles, surface tensions, fluorescence, and stability and analyzed them using polarized microscopy, atomic force microscopy, and attenuated total reflection Fourier transform infrared spectroscopy. Our one‐step emulsion process involved mixing lithospermum at various concentrations with three different emulsifiers to control the properties of the emulsion systems. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Preparation and properties of glass cloth‐reinforced polyimide composites with improved impact toughness for microelectronics packaging substrates
Authors: Xu Hong‐Yan , Yang Hai‐Xia , Tao Li‐Ming , Fan Lin , Yang Shi‐Yong
Published: March 2010

A series of glass cloth‐reinforced thermosetting polyimide composites (EG/HTPI) were prepared from E‐glass cloth (EG) and polyimide matrix resins. The polyimide resins were derived from 1,4‐bis(4‐amino‐2‐ trifluoromethyl‐phenoxy)benzene, p‐phenylenediamine, diethyl ester of 3,3′,4,4′‐benzophenonetetracarboxylic acid, and monoethyl ester of cis‐5‐norbornene‐endo‐2,3‐dicarboxylic acid. Based on the rheological properties of the B‐staged polyimide resins, the optimized molding cycles were designed to fabricate the EG/HTPI laminates and the copper‐clad laminates (Cu/EG/HTPI). Experimental results indicated that the EG/HTPI composites exhibited high thermal stability and outstanding mechanical properties. They had flexural strength of >534 MPa, flexural modulus of >20.0 GPa, and impact toughness of >46.9 kJ/m2. The EG/HTPI composites also showed good electrical and dielectric properties. Moreover, the EG/HTPI laminates exhibited peel strength of ∼ 1.2 N/mm and great isothermal stability at 288°C for 60 min, showing good potential for application in high density packaging substrates. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Interaction of vulcanization and reinforcement of CB on dynamic property of NR characterized by RPA2000
Authors: Zhao Fei , Shi Xinyan , Chen Xiang , Zhao Shugao
Published: March 2010

Vulcanization and reinforcement are two most important approaches to improve rubber properties. Effect of carbon black (CB) load level on curing process and properties of Natural rubber (NR) compounds and vulcanizates and interaction between vulcanization and reinforcement were characterized by Rubber Processing Analyzer (RPA2000). The incorporation of CB shortened the scorch delay time and prolonged curing time. Only after CB loading level reached about 20 phr, could effective CB network be formed that contributed to the formation of “Payne effect.” Dynamic elastic shear modulus G′ of filled NR compounds had a stronger dependence on strain than that of unfilled NR. There was a synergism between vulcanization and reinforcement on the improvement of shear modulus of NR compounds and vulcanizates. The elastic recovery of vulcanizates restricted the break of CB network through the rubber bridges formed between CB particles and helped the reformation of broken CB network. All these action amplified the reinforcement of CB. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Nonisothermal crystallization kinetics of polytetrafluoroethylene/solid glass microsphere composites
Authors: Wang Zhi‐Chao , Kou Kai‐Chang , Chao Min , Bi Hui , Yan Lu‐Ke
Published: March 2010

The nonisothermal crystallization behavior and kinetics of polytetrafluoroethylene (PTFE) and PTFE/solid glass microsphere (SGM) composites were investigated with differential scanning calorimetry at various cooling rates (ϕ's). Three methods, namely, the Jeziorny, Ozawa and Mo methods, were used to describe the nonisothermal crystallization process. The results show that the peak temperature, crystallinity (Xc), and crystallization half‐time were strongly dependent on the content of SGMs and ϕ. The SGMs in the PTFE/SGM composites exhibited a higher nucleation activity. The nonisothermal crystallization kinetics of PTFE and the PTFE/SGM composites was analyzed successfully with the Jeziorny and Mo methods; however, the Ozawa equation was invalid for the nonisothermal crystallization process. The crystallization activation energy determined with the Kissinger equation was remarkably lower when a small amount of SGMs (5%) was added and then gradually increased and finally became slightly lower than that of pure PTFE as the content of SGMs increased up to 25% in the composites. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Nitroalcohol induced hydrogel formation in amine‐functionalized polymers
Authors: Solomon Marissa R. , O'Connor Naphtali A. , Paik David C. , Turro Nicholas J.
Published: March 2010

Certain β‐nitroalcohols degrade under basic conditions or upon heating to form formaldehyde. This reaction provides an elegant approach to generate formaldehyde within a system at a desired time using the stimulus of pH or temperature. Using β‐nitroalcohols as a delivery agent for formaldehyde, polymer crosslinking can be induced via stimulus. Such an approach is akin to those used to prepare “self‐healing” polymers, which have received much attention recently. Herein, we describe the use of certain β‐nitroalcohols as a masked formaldehyde delivery system and demonstrate its use as a crosslinking agent of amine functionalized polymers to form hydrogels. We examine the temperature and pH dependence of 2‐nitro‐1,3‐propanediol and 2‐(hydroxymethyl)‐2‐nitro‐1,2‐propanediol on the rate and extent of gelation and characterize the resulting gel by swelling and FTIR experiments. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Flame‐retardant properties of soybean fabric modified with N‐methylol diakyl phosphonopropionamide
Authors: Vynias D
Published: March 2010

Soybean is a competitive production material for fibers as it is abundant and cost effective. However, an inherent deficiency of soybean fiber is its poor flame‐retardant performance. In this study, the effect of N‐methylol diakyl phosphonopropionamide (Pyrovatex CP) on the flame retardancy of soybean was investigated by the Limiting Oxygen Index (L.O.I.) and the vertical flammability test. Little benefit with regard to flame retardancy was found when soybean was treated with Pyrovatex CP in the absence of additives. However, the incorporation of Lyofix MLF in the finishing treatment (3% w/v) increased the L.O.I. values of soybean fiber and enhanced char formation as indicated by Thermogravimetric Analysis (TGA). Improved fastness to washing was observed at higher application levels of Lyofix MLF (6% w/v). X‐ray Photoelectron Spectroscopy (XPS) indicated that surface phosphorus (% atomic) was reduced following washing for all fabrics examined. In addition, the substantivity of Lyofix MLF to soybean surface was exhibited. The flame‐retardant treatment presented in this article is cost effective and results in wash‐durable flame‐retardant fabrics. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Effects of the vibration parameters of a hydraulic, dynamic injection‐molding machine on the properties of low‐density polyethylene samples in a plasticating process
Authors: Wang Quan , Qu Jinping
Published: March 2010

A novel, self‐made, hydraulic, and dynamic injection‐molding machine was used to mold low‐density polyethylene samples in a standard sample mold. These samples were tested for tensile strength, density, differential scanning calorimetry, and energy consumption of the molding process to explore the influences of the vibration frequency and amplitude on the properties of the products. The results show that the maximum tensile strength was enhanced by 6.1%, the density was higher by 0.34%, the melting point moved to a higher temperature by 1.7°C, and the power consumption of the whole molding process was lowered by 7.5% when the vibration was imposed. The changing regularity is presented. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Effects of dilution and charge trapping on the performance of a light‐emitting diode of poly(9‐vinylcarbazole) doped with poly[2‐methoxy‐5‐(2′‐ethyl hexyloxy)– 1,4‐phenylene vinylene]
Authors: Zhang Xinwen , Wu Zhaoxin , Wang Dongdong , Wang Dawei , Hou Xun
Published: March 2010

We report the electroluminescence (EL) enhancement of polymer light‐emitting diodes made by the dispersion of poly[2‐methoxy‐5‐(2′‐ethyl hexyloxy)–1,4‐phenylene vinylene] (MEH–PPV) into poly(9‐vinylcarbazole) (PVK). From the photoluminescence and EL spectra of the polymer blend films, we found that, because of the dilution effect, interchain interactions in MEH–PPV were reduced markedly. The EL spectrum indicated that the charge‐trapping effect contributed to the formation of excitons at the MEH–PPV centers and, thus, strongly enhanced EL. Because of the balance between increasing trapping centers and suppressing interchain interactions, the best device performance was achieved when the polymer blend contained 12% MEH–PPV and 88% PVK (weight ratio), and this also led to improved color purity of the polymer blend devices. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Effects of organically modified nanoclay on the transport properties and electrochemical performance of acid‐doped polybenzimidazole membranes
Authors: Hasani‐Sadrabadi Mohammad Mahdi , Dorri Nassir Mokarram , Ghaffarian Seyed Reza , Dashtimoghadam Erfan , Sarikhani Kaveh , Majedi Fatemeh S.
Published: March 2010

Nanocomposite polyelectrolyte membranes based on phosphoric acid (H3PO4) doped polybenzimidazoles (PBIs) with various loading weights of organically modified montmorillonite (OMMT) were prepared and characterized for direct methanol fuel cell (DMFC) applications. X‐ray diffraction analysis revealed the exfoliated structure of OMMT nanolayers in the polymeric matrices. An H3PO4–PBI/OMMT membrane composed of 500 mol % doped acid and 3.0 wt % OMMT showed a membrane selectivity of approximately 109,761 in comparison with 40,500 for Nafion 117 and also a higher power density (186 mW/cm2) than Nafion 117 (108 mW/cm2) for a single‐cell DMFC at a 5M methanol feed. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010