bluuebunny/crossref_metadata_2025 huggingface dataset:
ANNA‐3 anti‐neuronal nuclear antibody: Marker of lung cancer‐related autoimmunity
Authors: Chan Koon Ho , Vernino Steven , Lennon Vanda A.
Published: August 2002

Two anti‐neuronal nuclear antibodies (ANNA‐1 and ANNA‐2) are markers of paraneoplastic neurological autoimmunity related to small‐cell carcinoma. ANNA‐2 is also related to breast carcinoma. Here we define a third IgG specificity (ANNA‐3), identified in 11 patients (10 adults) by immunofluorescence screening of sera from approximately 68,000 patients with suspected paraneoplastic neurological syndromes. ANNA‐3 binds prominently to nuclei of cerebellar Purkinje neurons, not to cytoplasm, granular neurons, or enteric neurons, but distinctively to renal glomerular podocytes. Western blots revealed an approximately 170 kDa antigen, in cerebellum and small‐cell carcinoma. IgG eluted from this protein reproduced Purkinje and podocyte nuclear staining. ANNA‐2 in 8 of 32 cases bound to podocyte nuclei but not to the 170 kDa protein. Healthy subjects and control neurological and cancer patients lack ANNA‐3. Neurological accompaniments, subacute and usually multifocal, included sensory/sensorimotor neuropathies, cerebellar ataxia, myelopathy, brain stem and limbic encephalopathy. All of 9 adults followed had an intrathoracic neoplasm, seven biopsied within 7 months (five small‐cell lung carcinomas and two adenocarcinomas, one lung, one esophagus) and two imaged, one early, the other 3 years later. Thus, immunohistochemical and Western blot criteria can now identify six IgG markers of neurological autoimmunity related to small‐cell carcinoma, their frequency being ANNA‐1 > collapsin response‐mediator protein‐5 > amphiphysin > Purkinje cell cytoplasmic antibody‐2 = ANNA‐2 = ANNA‐3.
A nitric oxide donor induces neurogenesis and reduces functional deficits after stroke in rats
Authors: Zhang Ruilan , Zhang Li , Zhang Zhenggang , Wang Ying , Lu Mei , LaPointe Margot , Chopp Michael
Published: August 2002

The adult rodent brain is capable of generating neuronal progenitor cells in the subventricular zone, and in the dentate gyrus of the hippocampus, throughout the life of the animal. Signals that regulate progenitor cell proliferation, differentiation, and migration are not well known. We report that administration of a nitric oxide donor, (Z)‐1‐[N‐(2‐aminoethyl)‐N‐(2‐ammonioethyl) aminio]diazen‐1‐ium‐1,2‐diolate (DETA/NONOate), to young adult rats significantly increases cell proliferation and migration in the subventricular zone and the dentate gyrus. Treatment with DETA/NONOate also increases neurogenesis in the dentate gyrus. Furthermore, administration of DETA/NONOate to rats subjected to embolic middle cerebral artery occlusion significantly increases cell proliferation and migration in the subventricular zone and the dentate gyrus, and these rats exhibit significant improvements of neurological outcome during recovery from ischemic stroke. Administration of DETA/NONOate significantly increases cortical levels of guanosine monophosphate both in ischemic and nonischemic rats, supporting the role of nitric oxide in promoting cell proliferation and neurogenesis. Thus, our data indicate that nitric oxide is involved in the regulation of progenitor cells and neurogenesis in the adult brain. This suggests that nitric oxide delivered to the brain well after stroke may have therapeutic benefits.
Properties of cellulose/PAN blend membrane
Authors: He Chunju , Pang Fengjian , Wang Qingrui
Published: August 2002

The water flux of a cellulose/PAN blend membrane increased with the PAN content, while retention to glucosan T40 decreased. The water flux decreased and the retention increased with the whole solid content. The membrane obtained had a high ability to remove creatinine and urea. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 3105–3111, 2002; DOI 10.1002/app.10021
Synthesis of multifunctional polypropylene via solid phase cografting and its grafting mechanism
Authors: Zhang Li‐Feng , Guo Bao‐Hua , Zhang Zeng‐Min
Published: August 2002

Functional monomers, maleic anhydride (MAH) and vinyl acetate (VAc), were used as comonomers in the solid‐phase grafting of polypropylene (PP). Quantitative determination of the graft level of both MAH and VAc performed by titration and FTIR methods allowed for a good appreciation of the interaction of MAH and VAc. A product with high‐graft level of both VAc and MAH was obtained when the feeding molar ratio of MAH/VAc approached 1 : 1. The melt flow rate (MFR) of the grafted PP decreased with the increase in the feeding amount of VAc. It was proposed that MAH and VAc molecules could form a kind of stable transition state during the graft polymerization and that the reactivity of both monomers were enhanced. The resulting multifunctional PP offers possibility for the development of novel PP‐based polymer blends and composites, thus extending the application field of PP. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 929–935, 2002; DOI 10.1002/app.10121
Properties of cyclic phosphine oxide epoxy cured by diacids and anhydride
Authors: Shau Min‐Da , Lin Cho‐Wing , Yang Wan‐Hsu , Lin Hong‐Ru
Published: August 2002

New phosphorylated epoxy polymers were obtained with a cyclic phosphine oxide epoxy, 10‐phenylphenoxaphosphine‐3,8‐diglycidylester‐10‐oxide (EPCAO), cured with three types of curing agents: N,N′‐(4,4′‐diphenylsulfone)bis(trimellitimide) (DIDA), 10‐phenylphenoxaphosphine‐3,8‐dicarboxylic acid‐10‐oxide (PACO), and phthalic anhydride (PA). In addition, compositions of the new EPCAO synthesized with these three curing agents (DIDA, PACO, and PA) were used to make a comparison of EPCAO's curing reactivities and heat and flame retardancy with those of Epon828 and DEN438. The reactivities were measured by differential scanning calorimetry. Through the evaluation of thermogravimetric analysis, those polymers that were obtained through the curing reactions between the cyclic phosphine oxide epoxy resin and the three curing agents mentioned also demonstrated excellent thermal properties and a high char yield. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 950–961, 2002; DOI 10.1002/app.10146
Applications of bifunctional aldehydes to improve paper wet strength
Authors: Xu Gordon Guozhong , Yang Charles Qixiang , Deng Yulin
Published: August 2002

Glyoxal and glutaraldehyde behave very differently for improving wet strength of paper. It is found that glyoxal is very efficient for improving temporary wet strength of paper without the presence of a catalyst and exposure to elevated temperatures. When a metal salt, such as Zn(NO3)2, is used as a catalyst and the curing temperature is increased, the durable wet strength of glyoxal‐treated paper increases at the expense of its flexibility, as shown by reduced stretch and folding endurance. Glutaraldehyde is not able to provide any improvement in wet strength to paper, even under high curing temperatures, provided no catalyst is used. With the aid of a metal salt catalyst, glutaraldehyde imparts excellent durable wet strength to paper without significantly sacrificing folding endurance, and the wet strength of glutaraldehyde‐treated paper increases steadily as curing temperature increases. The different behavior of glyoxal and glutaraldehyde may be attributed to their different reactivity toward cellulose. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 2539–2547, 2002
Solid‐state structure of thermally crystallized syndiotactic polystyrene
Authors: Hodge K. , Prodpran T. , Shenogina N. B. , Nazarenko S.
Published: August 2002

The solid‐state structure of syndiotactic polystyrene (s‐PS) after crystallization from the melt and the glassy state was examined by differential scanning calorimetry (DSC), density, and X‐ray diffraction analysis. It was possible to prepare semicrystalline s‐PS containing either the pure α‐ or the pure β‐crystalline form by melt crystallizing s‐PS from 280 or 330°C. The measurements confirmed the low density of both crystalline forms, which in the case of α‐crystalline form was smaller and in the case of β‐crystalline form was only slightly larger than the density of the glassy amorphous s‐PS. An endeavor to introduce the crystalline phase in s‐PS through cold crystallization at constant temperature above the glass transition resulted in a complex ordered phase. This ordered phase, depending on the crystallization temperature, contained the planar chain mesomorphic phase and the α‐crystalline phase with a low degree of perfection (cold crystallization in the range 120–175°C) or a mixture of the α‐ and β‐crystalline forms with a high degree of perfection (cold crystallization in the range 210–260°C). The combination of DSC and X‐ray measurements enabled us to resolve the complex ordered structure in semicrystalline s‐PS after cold crystallization. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 2705–2715, 2002
Alkaline protease production by immobilized growing cells of Serratia marcescens with interpolymer complexes of P(TM‐co‐AAm)/PAA
Authors: Wang Hongzuo , Liu Shiyong , Wang Ying
Published: August 2002

The growing cells of Serratia marcescens (SM) were immobilized with the interpolymer complex carrier, which is formed by the cationic polymer, poly(allyltrimethyl ammonium chloride‐co‐acrylamide) [P(TM‐co‐AAm)], and poly(acrylic acid) (PAA). When the association degree of PAA is suitable to the cationic degree of P(TM‐co‐AAm), the effective crosslinking network provides the most favorable circumstances for the cell immobilization. The alkaline protease can be produced by the immobilized SM with high activity. Compared with the free cells, the immobilized SM has higher thermal stability, acid‐base stability, operational stability, and storage stability. Under the optimum immobilizing conditions, not only the living cells of SM but also thermophilic Bacillus firmus (TBF) were immobilized with the complex of P(TM‐co‐AAm)/PAA. The results show the carrier of P(TM‐co‐AAm)/PAA complex to be superior in properties to the usual carriers, such as Na‐alginate and carrageenan. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 178–183, 2002; DOI 10.1002/app.10293
Colon‐specific oral delivery of vitamin B2 from poly(acrylamide‐co‐maleic acid) hydrogels: An in vitro study
Authors: Bajpai S. K. , Bajpai M. , Kalla K. G.
Published: August 2002

Hydrogels, composed of poly(acrylamide‐co‐maleic acid) were synthesized and the release of vitamin B2 from these gels was studied as a function of the pH of the external media, the initial amount of the drug loaded, and the crosslinking ratio in the polymer matrix. The gels containing 3.8 mg of the drug per gram gel exhibit almost zero‐order release behavior in the external media of pH 7.4 over the time interval of more than their half‐life period (t1/2). The amount of the drug loaded into the hydrogel also affected the dynamic release of the encapsulated drug. As expected, the gels showed a complete swelling‐dependent mechanism, which was further supported by the similar morphology of the swelling and release profiles of the drug‐loaded sample. The hydrophilic nature of the drug riboflavin does not contribute toward the zero‐order release dynamics of the hydrogel system. On the other hand, the swelling osmotic pressure developed between the gels and the external phase, due to loading of the drug by equilibration of the gels in the alkaline drug solution, plays an effective role in governing the swelling and release profiles. Finally, the minimum release of the drug in the swelling media of pH 2.0 and the maximum release with zero‐order kinetics in the medium of pH 7.4 suggest that the proposed drug‐delivery devices have a significant potential to be used as an oral drug‐delivery system for colon‐specific delivery along the gastrointestinal (GI) tract. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 1133–1145, 2002; DOI 10.1002/app.10402
Properties of ligno‐cellulose fiber Hildegardia
Authors: Rajulu A.Varada , Rao G. Babu , Rao B. Ravi Prasad , Reddy A. Madhu Sudana , He Jiasong , Zhang Jun
Published: August 2002

Studies on some properties such as the density, the degradation temperatures, the morphology and the spectral features of the ligno‐cellulose fiber Hildegardia were carried out in both untreated and alkali treated form. The fibers are found to have good morphology and moderate initial and final degradation temperatures. On alkali treatment, the lignin was found to be eliminated. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 2216–2221, 2002
Rheological properties of metallocene isotactic polypropylenes
Authors: Fujiyama Mitsuyoshi , Inata Hitoshi
Published: August 2002

Rheological properties of metallocene‐catalyzed isotactic polypropylenes (MET‐PP) were evaluated in comparison with those of Ziegler–Natta‐catalyzed isotactic polypropylenes (ZN‐PP) and MET‐PP was generally characterized in a rheological aspect. Based on the characterization, various flow processibilities and their effect on the higher order structure and product properties of the processed article were estimated. The capillary flow properties at various temperatures, elongational flow properties, and dynamic viscoelasticities of MET‐PPs and ZN‐PPs with various melt flow indexes (MFIs) were measured. Furthermore, as an example of application of rheological analysis, the selection of proper raw resin and processing conditions in the sheet‐extrusion of MET‐PP was studied. MET‐PP shows the following rheological features due mainly to the narrow molecular weight distribution in comparison with ZN‐PP with equivalent MFI to that of MET‐PP: while the viscosities at low shear rates are lower, those at high shear rates are higher. Although there is little difference in the loss modulusG″ (viscosity), the storage modulusG′ (elasticity) is very (about one decade) lower. The die swell is much smaller. The entrance pressure loss and end correction coefficient are lower. The critical shear rate at which a melt fracture begins to occur is lower. The melt tension, elongational viscosity, and melt flow index ratio are lower. The flow activation energy is slightly lower. The zero‐shear viscosity obeys the 3.4th‐power law independent of catalyst. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 2157–2170, 2002
Preparation of silk fibroin and polyallylamine composites
Authors: Arai T. , Wilson D. L. , Kasai N. , Freddi G. , Hayasaka S. , Tsukada M.
Published: August 2002

Composite films made of silk fibroin (SF) and polyallylamine (PAA) are prepared that contain various compositional ratios. These materials are analyzed to elucidate the resulting physical properties and to assess their potential toward advanced applications as industrial materials. The composite films are obtained from a SF and PAA binary system by dry casting from aqueous solution. These composite films exhibit excellent processability such as film forming capabilities, and the elongation at break is increased in the wet state. The differential scanning calorimetry (DSC) curves of the composites suggest that a mutual interaction takes place between the SF and PAA. This interaction is believed to occur because the endothermic peak, corresponding to the individual polymer, shifts with increasing SF content. The random coil conformation of the SF is present, regardless of the PAA blending, as confirmed by FTIR and DSC measurements. Additionally, living cells from Antheraea pernyi and Bombyx mori insect tissues are shown to grow effectively on the composite films. Maximum growth levels occur when the cultivation flask is coated with the material in SF/PAA ratios of 75:25 to 25:75. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 1963–1970, 2002; DOI 10.1002/app.10491
A novel approach for albumin determination in aqueous media by using temperature‐ and pH‐sensitive N‐isopropylacrylamide‐co‐N‐[3‐(dimethylamino)‐propyl]methacrylamide random copolymers
Authors: Tuncel A. , Demirgöz D. , Patir S. , Piskin E.
Published: August 2002

Random copolymers of N‐isopropylacrylamide (NIPA) and N‐[3‐(dimethylamino)propyl]methacrylamide (DMAPM) were synthesized by solution polymerization using azobisizobutyronitrile as the initiator in 1,4‐dioxane at 60°C. NIPA‐co‐DMAPM copolymer exhibited both temperature and pH sensitivity. Thermally reversible phase transitions were observed both in the acidic and the alkaline pH regions for copolymers produced with different DMAPM/NIPA feed ratios. The pH dependency of the lower critical solution temperature (LCST) was stronger for copolymers produced with higher DMAPM feed concentrations. NIPA‐co‐DMAPM random copolymer was also sensitive to the albumin concentration. In the presence of albumin, thermally irreversible phase transitions were observed in slightly acidic and neutral media. However, reversible transitions were obtained in aqueous media containing albumin at basic pH. The phase‐transition temperature of NIPA‐co‐DMAPM copolymer significantly decreased with increasing albumin concentration at both acidic and alkaline pH values. This behavior was explained by albumin binding onto the copolymer chains by means of H‐bond formation between the dimethylamino groups of the copolymer and the carboxyl groups of albumin. For a certain range of albumin concentration, the phase‐transition temperature exhibited a linear decrease with increasing albumin concentration. By utilizing this behavior, a simple albumin assay was developed. The results indicated that NIPA‐co‐DMAPM copolymer could be utilized as a new reagent for the determination of albumin concentration in the aqueous medium. The proposed method was valid for the albumin concentration range of 0–4000 μg/mL. The protein concentrations commonly utilized in biotechnological studies fall in the range of the proposed method. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 2060–2071, 2002; DOI 10.1002/app.10503
Analysis of the effects of the polymerization route of ethylene‐propylene‐diene rubbers (EPDM) on the properties of polypropylene‐EPDM blends
Authors: López‐Manchado Miguel A. , Kenny José M.
Published: August 2002

A comparative study of two ethylene‐propylene‐diene rubbers (EPDM) polymerized by both conventional (Ziegler–Natta catalysts) and new techniques (metallocene catalysts) is presented. For this purpose, thermoplastic elastomers based on isotactic polypropylene (iPP) and EPDM blends at different percentages were prepared and their properties examined. In particular, the processing behavior and mechanical properties are reported. So, the flow properties analyzed by torque value, melt index, and rheological study reveal that the blends containing EPDM synthesized by metallocene catalyst present a smaller viscosity, thus offering better processing behavior. On the other hand, the mechanical properties show that metallocene EPDM rubbers give rise to more elastic materials with a higher deformation at break and resilience as well as a lower compression set. Moreover, the effectiveness of these innovative EPDM rubbers as impact modifiers for PP is demonstrated. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 25–37, 2002
Water‐soluble acrylamide copolymers. X. Flocculation efficiencies of poly[acrylamide‐co‐N,N‐dimethylacrylamide], poly[acrylamide‐co‐methacrylamide], poly[acrylamide‐co‐N‐t‐butylacrylamide], and their cationic derivatives
Authors: Hocking Martin B. , Klimchuk Keith A. , Lowen Stephen
Published: August 2002

A hydrated, 1% by weight Na‐kaolinite suspension in deionized water was prepared, completely characterized, and reproducible measures of flocculation efficiency were validated. Flocculation tests of copolymers of acrylamide (AM) with dimethylacrylamide (DMA), methacrylamide (MeAM), or N‐t‐butylacrylamide (NTBAM) with 1% Na‐kaolinite suspensions gave average settling rate rates which decreased as the proportion of DMA, MeAM, or NTBAM in the copolymer increased. However, for a similar weight‐average molecular weight and slightly lower 〈rg〉, the copolymer from DMA‐co‐AM‐3 gave settling rates and supernatant turbidities comparable to similar types of commercial polymers. This new copolymer was also more resistant to changes in pH or the presence of an electrolyte than were the tested commercial polymers. Cationic derivatives of the new copolymers gave lower average settling rates and higher supernatant turbidities than those of Percol 721 (cationic PAM), probably because of their lower charge densities. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 2090–2108, 2002; DOI 10.1002/app.10562
Improvement of conductive network quality in carbon black‐filled polymer blends
Authors: Hou Yan Hui , Zhang Ming Qiu , Rong Min Zhi , Yu Gang , Zeng Han Min
Published: August 2002

Heat treatment of polymer‐based composites is critical for the enhancement of both stability and long‐term service life, especially when the materials function under an inconstant temperature environment. The present article discusses the effect of heat‐treatment conditions on the electrically conductive properties of carbon black (CB)‐filled low‐density polyethylene (LDPE) and ethylene–vinyl acetate copolymer (EVA) composites, which are candidates for positive temperature coefficient (PTC) materials. It was found that the dispersion mode of CB particles changes as a function of the matrix morphology. When the composites are irradiated to form crosslinked networks in the matrix for the elimination of negative temperature coefficient (NTC) behavior, some of the produced free radicals are also entrapped for quite a long time after the irradiation treatment. These residual radicals further enhance the interaction between CB and the matrix and further induce the crosslinking of the matrix so that the composites' conductivity changes with time as a result of the continuous variation in the contacts between the conductive fillers. To improve the quality of the conduction paths in the composites, appropriate post‐heat treatment should be carried out, which speeds up the formation of the above‐mentioned two kinds of crosslinked structures within a limited time. Annealing at 75°C for more than 10 h is believed to be an effective way. After the treatment, a balanced performance characterized by reduced room‐temperature resistivity and improved PTC intensity was obtained. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 2768–2775, 2002
Some studies on mechanical properties of wood flour/continuous glass mat/polypropylene composite
Authors: Lin Qunfang , Zhou Xiaodong , Dai Gance , Bi Yiemao
Published: August 2002

The mechanical properties and the surface property of wood flour/continuous glass mat/polypropylene composites have been investigated. The suitability of wood flour as a filler for continuous glass mat–reinforced polypropylene has been tested using different mesh sizes (e.g., 20 and 40 mesh), as well as by varying the weight percentage of wood flour from 0%– 30%. Moreover, different treatments such as coupling agent A‐1100 and functionalized polypropylene grafting with maleic anhydride, and so forth, have also been used to improve the compatibility of wood flour and glass fiber with the polymer resin. In addition, the effects of the surface weight of glass mat and matrix resin have been studied. The extent of the improvement in mechanical properties depends on the wood flour content and size, the surface weight of the glass mat, the matrix resin, and the surface treatment of wood flour. After adding wood flour, the contact angle of distilled water on the composite surface decreases and the polar component of surface tension increases. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 536–544, 2002
Properties of silica‐filled styrene‐butadiene rubber compounds containing acrylonitrile‐butadiene rubber: The influence of the acrylonitrile‐butadiene rubber type
Authors: Choi Sung‐Seen
Published: August 2002

Because silica has strong filler‐filler interactions and adsorbs polar materials, a silica‐filled rubber compound exhibits poor dispersion of the filler and poor cure characteristics in comparison with those of a carbon black‐filled rubber compound. Acrylonitrile‐butadiene rubber (NBR) improves filler dispersion in silica‐filled styrene‐butadiene rubber (SBR) compounds. The influence of the NBR type on the properties of silica‐filled SBR compounds containing NBR was studied with NBRs of various acrylonitrile contents. The composition of the bound rubber was different from that of the compounded rubber. The NBR content of the bound rubber was higher than that of the compounded rubber; this became clearer for NBR with a higher acrylonitrile content. The Mooney scorch time and cure rate became faster as the acrylonitrile content in NBR increased. The modulus increased with an increase in the acrylonitrile content of NBR because the crosslink density increased. The experimental results could be explained by interactions of the nitrile group of NBR with silica. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 385–393, 2002
Structural aspects and nature of swelling medium as equilibrium swelling determinants of acrylamide and cellulosic‐based smart hydrogels
Authors: Chauhan Ghanshyam S. , Mahajan Swati
Published: August 2002

Hydroxypropylcellulose (HPC)‐based interpenetrating networks (IPN) with acrylamide (AAm) were synthesized in aqueous medium by simultaneous γ‐ray initiation in the presence of N,N‐methylenebisacrylamide (N,N‐MBAAm). The effect of the synthetic reaction conditions was evaluated for optimum network yield and networks of cellulose and some of its derivatives were obtained with AAm by using these conditions. FTIR, elemental analysis, and scanning electron micrography (SEM) for various structural aspects have characterized networks. Apart from kinetics of IPN formation, this article discusses swelling response of these novel hydrogels in different swelling media. Swelling behavior was studied as a function of synthetic reaction conditions, structure of cellulosics used, and nature of swelling medium (water, 0.5N NaOH, 0.5N HCl, and 5% NaCl). Equilibrium swelling was observed to depend on both structural and environmental factors. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 1161–1169, 2002
High‐pressure differential thermal analysis of polymers
Authors: Kojima Yoshitsugu , Takahara Minoru , Matsuoka Takaaki , Takahashi Hideroh
Published: August 2002

Melting behavior under high pressure of nylon 6, nylon 6‐clay hybrid (NCH) and poly(butylene terephthalate) was investigated by high‐pressure differential thermal analysis (DTA). It was found that the melting temperature and the pressure dependency of the melting temperature of NCH were low compared with those of nylon 6. Using the melting temperature, the pressure dependency of the melting temperature, and the heat of fusion (the enthalpy of fusion), the Clausius‐Clapeyron equation was used to determine the volume changes on melting of the polymers at atmospheric pressure ΔVm0(DTA). ΔVm0(DTA) of NCH was lower than that of the nylon 6 α‐form. The smaller ΔVm0(DTA) of NCH was attributed to the presence of nylon 6 γ‐form in NCH. The values of ΔVm0(DTA) for nylon 6 and poly(butylene terephthalate) were similar to those obtained from pressure‐volume‐temperature relationships ΔVm0(PVT) of those polymers. The entropies of fusion were constant and independent of pressures up to 100 MPa. The volume changes on melting (ΔVm in cm3/g) under high pressure can be approximately described by the following equation: ΔVm = 0.165TmVw (dTm/dP)/(dTm0/dP)/298, where Tm and Tm0 are the melting temperatures (in K) under high pressure and atmospheric pressure, respectively and Vw is the van der Waals volume of the polymer (cm3/g). © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 1046–1051, 2001
Expandable graphite systems for halogen‐free flame‐retarding of polyolefins. II. Structures of intumescent char and flame‐retardant mechanism
Authors: Xie Rongcai , Qu Baojun
Published: August 2002

The structures of the intumescent charred layers formed from polyolefin (PO) blends with expandable graphite (EG) and/or the other free‐halogen flame retardant (HFFR) and their flame‐retardant mechanism were studied by Fourier transform infrared (FTIR) spectroscopy, X‐ray photoelectron spectroscopy (XPS), laser Raman spectroscopy (LRS), scanning electron microscopy (SEM), differential thermal analysis (DTA), and thermal conductivity (TC) measurements. The FTIR, XPS, and LRS data showed that the carbonaceous structures of intumescent charred layers consist of EG and various numbers of condensed benzene rings and/or phosphocarbonaceous complexes attached by the P—O—C and P—N bonds or quaternary nitrogen or dehydrated zinc borate (ZB). These results and the morphologic structures observed by SEM have demonstrated that the compact structures of charred layers slow down heat and mass transfer between the gas and condensed phase and prevent the underlying polymeric substrate from further attack by heat flux in a flame. The DTA data provide the positive evidence for the flame‐retardant mechanism of the PO/EG/HFFR systems, which works by increasing the oxidation temperature and decreasing thermal oxidation heat. At the same time, the TC data reveal the flame‐retardant essence of the charred layers as good heat‐insulated materials whose TC value is only about 1/10 of the corresponding blend. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 1190–1197, 2001
Melt/solution processable polyaniline with functionalized phosphate ester dopants and its thermoplastic blends
Authors: Paul Raji K. , Pillai C. K. S.
Published: August 2002

Polyaniline (PANI) was doped with five novel dopants, 3‐pentadecylphenylphosphoric acid (PDPPA), pentadecylphenyl(bis)phosphoric acid [PDP(bis)PA], monocardanylphosphoric acid (MCPA), dicardanylphosphoric acid (DCPA), and phosphorylated cashew nut shell liquid prepolymer (PCNSL) and the doping behavior was studied. All dopants were synthesized from inexpensive naturally existing monomers [obtained from cashew nut shell liquid (CNSL)] having a long hydrophobic hydrocarbon side chain in the meta position of the aromatic ring. These dopants can act as plasticizing cum protonating agents for PANI so that free‐standing films of PANI could be prepared by both thermal processing and solution processing techniques. Protonation was performed either by mechanical mixing of emeraldine base and the dopant or by an in situ doping emulsion polymerization route using xylene or chloroform as the solvent. Further, conductive flexible blends of the protonated PANI with poly(vinyl chloride) (PVC) were also prepared and studied for their conductivity and related properties. The PANI–PDPPA complex obtained by the in situ doping emulsion polymerization route exhibited an exceptionally high degree of crystalline order and orientation. A maximum conductivity value of 1.8 S cm−1 was obtained for a PANI–PDPPA film hot‐pressed at 120°C. On the other hand, dopants based on cardanol having an unsaturated side chain gave only lower values. This was understood to be due the capability of the saturated analog to contribute to the ordered arrangement of PANI, thus improving the crystallinity. The conductivity values further decreased when bulky/oligomeric dopants such as PCNSL were used. The thermoplastic blends with PVC exhibited an exceptionally low‐level percolation threshold because of the plasticizing nature of the dopants. The doped polymers and blends were characterized by FTIR and UV‐visible spectroscopic methods, four‐probe conductivity measurements, XRD, SEM, TGA, and DSC. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 1354–1367, 2001
Ring‐banded spherulites in poly(ϵ‐caprolactone) blended with hydroxyethyl cellulose acetate as an indication for partial miscibility
Authors: Xiao Q. , Yan S. , Rogausch K. D. , Petermann J. , Huang Y.
Published: August 2002

The morphologies of poly(ϵ‐caprolactone) (PCL) blends with hydroxyethyl cellulose acetate (HECA), a thermotropic liquid crystalline polymer (TLCP), were investigated by optical microscopy. It is demonstrated that when the pure PCL is crystallized from the melt, a spherulitic morphology arises with distinct Maltese crosses. With the addition of the HECA, the spherulites of the PCL/HECA blends show not only the Maltese crosses but also distinct extinction rings (i.e., a ring‐banded spherulitic morphology). The average periodic distance of the extinction rings decreases drastically with the increase of the HECA content from 0.5 to 5 wt % in the mixture, whereas it decreases only slightly with the further increase of HECA. The periodicity of extinction rings is also influenced by the crystallization temperature. The formation of the ring‐banded spherulites of PCL in PCL/HECA blends is explained in terms of stress‐induced twisted lamellar crystallization and used as an indication of the molecular solubility of the HECA in the PCL. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 1681–1686, 2001
Synthesis and characterization of poly(hydroxyether). I. Poly(hydroxyether) based on 2,2‐bis(4‐hydroxyphenyl)hexafluoropropane and 2,2‐bis(4‐hydroxyphenyl)propane
Authors: Fukuoka Tetsuya , Tatehata Hideki , Mochizuki Akira
Published: August 2002

Linear poly(hydroxyethers) (PHEs) were prepared by the base‐induced condensation of bisphenols with epichlorohydrin in a polar mixed solvent. The bisphenols used were 2,2‐bis(4‐hydroxyphenyl)propane (bisphenol A) and 2,2‐bis(4‐hydroxyphenyl)‐hexafluoropropane (bisphenol AF). Bisphenol A–based homo‐PHE (HPHE‐A), bisphenol AF–based homo‐PHE (HPHE‐AF), and copoly(hydroxyethers) (CPHEs) based on both the bisphenols with various compositions were characterized in terms of chemical structure, thermal property, solubility, and contact angle. The incorporation of bisphenol AF unit into HPHE‐A brought about the increases in the glass‐transition temperature, the solubility in organic solvents, and the hydrophobicity. The sequence of the repeating unit in the copolymer was analyzed by 1H–NMR and the result agreed well with the one calculated as a random copolymer. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 1687–1696, 2001
Advanced torsional dynamic methods to study the morphology of uncured filled rubber compounds
Authors: Leblanc Jean L. , Cartault Marie
Published: August 2002

Uncured compounds of SBR1500 with various levels of silica were studied using a torsional dynamic tester (rubber process analyzer; RPA). Silica‐filled compounds were prepared with the appropriate amounts (8.2%) of silane, i.e., bis(3‐triethoxysilylpropyl)tetrasulfane (TESPT). A carbon black‐filled compound was also studied for comparison. Strain sweep tests at constant frequency show that filled rubber materials exhibit either no or limited linear viscoelastic domain. Frequency sweep tests were performed either at the lowest strain amplitude or within the linear range at several temperatures; results were treated through time–temperature superposition in order to yield G′ and G″ master curves at the reference temperature of 100°C. Special test procedures were applied that are known to give interesting information about the morphology of complex polymer systems: the morphology damaging test (MDT) and the damaged morphology recovery test (DMRT). Results obtained are discussed with respect to the likely morphology of carbon black and silica‐filled rubber compounds. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 2093–2104, 2001
TTT and CHT curing diagrams of water‐borne polycondensation resins on lignocellulosic substrates
Authors: Pizzi A. , Zhao C. , Kamoun C. , Heinrich H.
Published: August 2002

Lignocellulosic substrates such as wood were found to have a marked modifying influence on both lower temperature and higher temperature zones of TTT and CHT diagrams during hardening of phenol–resorcinol–formaldehyde (PRF) and melamime–urea–formaldehyde (MUF) polycondensates. Although the modifying influence of the substrate on the higher temperature zone of CHT diagrams presented the same trend of what was already reported for phenol–formaldehyde (PF) and urea–formaldehyde (UF) polycondensates, marked differences from what reported in the literature were recorded for TTT diagrams of all these polycondensates as well for the lower temperature zones of the CHT diagrams on lignocellulosic substrates, both of which had not been investigated previously. The chemical and physical mechanisms of the interactions of the resins, the substrate, and the water carrier causing such marked variations are presented and discussed. Although in the higher temperature zones both substrate and water carrier play an important role, in the lower temperature zone the presence of water appears to be the dominant factor causing the observed variations. The generalized modified CHT and TTT diagrams characteristic of the behavior of these water‐borne polycondensates on lignocellulosic substrates can be used to describe the behavior and complex changes of phase the formaldehyde‐based polycondensation resins undergo when used as wood adhesives during their curing directly in the wood joint. The results also show that diagrams obtained with pure resin cannot be used to predict the behavior of the polycondensate when this is markedly modified by the presence of interacting solvents and substrates. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 2128–2139, 2001
Structure, processing, morphology, and property relationships of biaxially drawn Ziegler–Natta/metallocene isotactic polypropylene film
Authors: Phillips Roger A. , Nguyen Tinh
Published: August 2002

The structure, processing, morphology, and property relationships of biaxially drawn isotactic polypropylene (BOPP) film of mixed metallocene isotactic PP (m‐iPP) and Ziegler–Natta iPP (ZN‐iPP) homopolymer compositions are developed. The DSC and film drawing behavior show cocrystallization of the ZN‐iPP and m‐iPP components. The structure, processing, morphology, and property relations of ZN‐iPP/m‐iPP blends are compared with ZN‐iPP of varying isotacticities. The ZN‐iPP/m‐iPP blends exhibit reduced biaxial yield stress [σy(T)]. A fractional crystallinity model collapses the σy(T) data into a common normalized form over a range of draw temperatures, ZN‐iPP tacticities, and blend compositions. The simplified model is extended to define the interrelationships of yield activation and strain hardening behavior into regimes differentiated by characteristic draw stress (crystallinity) levels. Structure–property models are developed to explain the effect of draw temperature and resin–blend microstructure on the draw behavior, film stiffness, barrier, elongation, and synergies of the BOPP film processing–property balance. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 2400–2415, 2001
Cure and mechanical properties of filled SMR L/ENR 25 and SMR L/SBR blends
Authors: Poh B. T. , Ismail H. , Quah E. H. , Chin P. L.
Published: August 2002

The effect of blend ratio of natural rubber/epoxidized natural rubber (SMR L/ENR 25) and natural rubber/styrene‐butadiene rubber (SMR L/SBR) blends on scorch time (t2), cure time (t90), resilience, hardness, and fatigue properties were studied in the presence of carbon black and silica. An accelerated sulfur vulcanization system was used throughout the investigation. The scorch and cure times of the rubber compound were assessed by using a Moving‐Die Rheometer (MDR 2000). Resilience, hardness, and fatigue life were determined by using a Wallace Dunlop Tripsometer, a Wallace Dead Load Hardness Tester, and a Fatigue to Failure Tester, respectively. The results indicate that t2 and t90 decrease with increasing ENR 25 composition in the SMR L/ENR 25 blend whereas both values increase with increasing SBR content in the SMR L/SBR blend. This observation is attributed to faster cure in ENR 25 and higher saturation in SBR. Resilience decreases with increase in % ENR and % SBR but hardness shows the reverse behavior in their respective blends. The fatigue life increases with % ENR, but it passes through a maximum with % SBR in the respective blends. In all cases, aging lowers the fatigue life, a phenomenon that is caused by the breakdown of crosslinks in the vulcanizate. Differences in all the observed values between carbon black‐filled and silica‐filled blends are associated with the varying degrees of interaction and dispersion of the two fillers in the rubber blend matrix. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 47–52, 2001
Synthesis of amphiphilic microspheres by suspension copolymerization of styrene and poly(ethylene oxide) macromonomer
Authors: Li Wei , Ding Xiao‐Bing , Zheng Zhao‐Hui , Zhang Wen‐Chuan , Deng Jing‐Gen , Peng Yuxing , Chan Albert S. C. , Yip C. W.
Published: August 2002

Amphiphilic microspheres, ranging in size from 3 to 35 μm, were prepared by suspension copolymerization of styrene with poly(ethylene oxide) vinylbenzyl (PEO–VB) macromonomer by changing polymerization conditions. It was found that an increase in the amount of dispersant and the PEO–VB concentration resulted in decreases of the size and size distribution of amphiphilic microspheres. The morphology, size, and size distribution of amphiphilic microspheres were characterized by scanning electron microscopy. The structure of copolymer was confirmed by infrared spectroscopy, differential scanning calorimetry, elemental analysis, and X‐ray photoelectron spectroscopy. The content of the hydroxyl groups localized in the microspheres ranged from 0.05 to 0.2 mmol/g. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 333–339, 2001
Condition monitoring of a thermally aged hydroxy‐terminated polybutadiene (HTPB)/isophorone diisocyanate (IPDI) elastomer by nuclear magnetic resonance cross‐polarization recovery times
Authors: Assink Roger A. , Lang David P. , Celina Mathew
Published: August 2002

A hydroxy‐terminated polybutadiene (HTPB)/isophorone diisocyanate (IPDI) elastomer is commonly used as propellant binder material. The thermal degradation of the binder is believed to be an important parameter governing the performance of the propellant. The aging of these binders can be monitored by mechanical property measurements, such as modulus or tensile elongation. These techniques, however, are not easily adapted to binder agents that are dispersed throughout a propellant. In this paper we investigated solid‐state nuclear magnetic resonance (NMR) relaxation times as a means to predict the mechanical properties of the binder as a function of aging time. Proton (1H) spin–lattice and spin–spin relaxation times were insensitive to the degree of thermal degradation of the elastomer. Apparently, these relaxation times depend on localized motions that are only weakly correlated with mechanical properties. A strong correlation was found between the 13C cross‐polarization (CP) NMR time constant, Tcp, and the tensile elongation at break of the elastomer as a function of aging time. A ramped‐amplitude CP experiment was less sensitive to imperfections in setting critical instrumental parameters for this mobile material. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 453–459, 2001
Improved surface characteristics and the conductivity of polyaniline–nylon 6 fabrics by plasma treatment
Authors: Oh Kyung Wha , Kim Seong Hun , Kim Eun Ae
Published: August 2002

The effect of plasma treatment on the surface characteristics and conductivity of polyaniline–nylon 6 composite fabrics was investigated. Plasma surface modifications with oxygen, ammonia, and argon were performed on the nylon 6 fabrics to improve the adhesion and rate of polymerization. The surface morphology of the fiber was observed with scanning electron microscopy, and functional groups introduced onto the surface of nylon 6 fibers by various plasma treatments were characterized by X‐ray photoelectron spectroscopy. With oxygen plasma treatment, the fiber surface was effectively etched; polar groups such as OH and OOH were introduced onto the surface of nylon 6 fiber, and they increased surface activity, promoted oxidation polymerization, and resulted in higher add‐on and electrical conductivity. However, the introduced amine and amide groups with ammonia treatment caused a reduction in conductivity. Argon did not significantly alter the surface characteristics of the nylon 6 fibers. In addition, to control fabric conductivity and cover as wide a range of conductivity as possible, we observed the effects of the monomer concentration and number of deposits on the fabric conductivity. The results showed that fabric conductivity increased as the monomer concentration increased up to 0.5M and then leveled off, and further increases were achieved with an increase in the number of multiple deposits. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 684–694, 2001
Preparation of poly(vinyl butyral) with high acetalization rate
Authors: Chetri P. , Dass N. N.
Published: August 2002

Poly(vinyl alcohol) (PVA) can be dissolved in a nonaqueous medium in the presence of catalytic concentration of ethyl nitrate dimethyl sulfoxide, C2H5ONO2 · DMSO (EN · DMSO). From the PVA solution, poly(vinyl butyral) (PVBu) was prepared by acid‐catalyzed homogeneous acetalization of PVA with butyraldehyde. The formation of PVBu was confirmed by IR and 1H‐NMR spectra. The degree of acetalization of PVBu was found to be 95 mol %, which was verified by 1H‐NMR data and acetylation method. The molecular mass of the polymer was determined by GPC method. The glass transition temperature, Tg, was measured from differential scanning calorimetric (DSC) thermograms. Thermal stabilities were checked by thermogravimetric analysis (TGA) and differential thermogravimetry (DTG). The acetal decomposed in three stages. The corresponding initial decomposition temperatures were found to be 285, 390, and above 500°C. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 1182–1186, 2001
Influence of preparation parameters on the CHT curing diagrams of MUF polycondensation resins
Authors: Properzi M. , Pizzi A. , Uzielli L.
Published: August 2002

Lignocellulosic substrates such as wood have been found to have a marked modifying influence on both lower‐temperature and higher‐temperature zones of TTT and CHT diagrams during hardening of formaldehyde‐based polycondensates. While the modifying influence of the substrate has been described, the modifying influence of some of the most important manufacturing parameters of the resins on the CHT diagram, not having been previously investigated, are explored here and clear trends are shown. In the case of melamine–urea–formaldehyde (MUF) resins for wood adhesives, the molar ratio (M+U):F appear to be the dominant parameter influencing the relative position of gel and vitrification curves in relation to each other. The ratio of melamine to urea does not appear to have any effect on the relative position of the curve, lacking any clear trend, at least at the higher (M+U) molar ratio of 1:1.9 used for this series of resins. In the case presented for the first time, the influence of resin manufacturing parameters on CHT curing diagrams was studied in combination with the modifications introduced by the substrate. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 2821–2825, 2001
Slightly crosslinked poly(N‐vinylcaprolactam) gels as the media for growth of copper(II) sulfate pentahydrate crystals
Authors: Nasimova I. R. , Evlanova N. F. , Makhaeva E. E. , Khokhlov A. R.
Published: August 2002

The behavior of slightly crosslinked poly(N‐vinylcaprolactam) (PVCa) gels in a CuSO4 solution in water and ethanol was studied. The investigation was carried out for PVCa gels with polymer contents of 4% and 7%. The effective absorption of CuSO4 by PVCa hydrogel accompanied by gel shrinking was observed for the CuSO4 aqueous solution. It was shown that dendrite crystals of CuSO45H2O localized within the gel sample are obtained after placement of gels samples into ethanol. The crystal habit depends on gel concentration. It was found that slightly crosslinked PVCa gels are promising as media for the growth of crystals. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 2838–2842, 2001