bluuebunny/crossref_metadata_2025 huggingface dataset:
US Suicide Rates by Age Group, 1970–2002: An Examination of Recent Trends
Authors: McKeown Robert E. , Cuffe Steven P. , Schulz Richard M.
Published: September 2006

US suicide rates have declined in recent years, reversing earlier trends. We examined suicide rates among 4 age groups from 1970 to 2002 and the factors that may have contributed to the decline. We paid particular attention to newer anti-depressants because of recent concerns and controversy about a possible association with suicidal behaviors. These trends warrant more extensive analysis of suicide rates among specific subgroups, including consideration of additional variables that may influence rates differentially.

The relative contributions of depression diagnosis and treatment, postsuicide attempt care, and other contextual factors (e.g., overall economic conditions) also deserve attention. If the decline is associated with contextual factors, clarifying these associations will better inform public policy decisions and contribute to more effective interventions for preventing suicide.
Communal Housing Settings Enhance Substance Abuse Recovery
Authors: Jason Leonard A. , Olson Bradley D. , Ferrari Joseph R. , Lo Sasso Anthony T.
Published: September 2006

Oxford Houses are democratic, mutual help–oriented recovery homes for individuals with substance abuse histories. There are more than 1200 of these houses in the United States, and each home is operated independently by its residents, without help from professional staff.

In a recent experiment, 150 individuals in Illinois were randomly assigned to either an Oxford House or usual-care condition (i.e., outpatient treatment or self-help groups) after substance abuse treatment discharge. At the 24-month follow-up, those in the Oxford House condition compared with the usual-care condition had significantly lower substance use, significantly higher monthly income, and significantly lower incarceration rates.
Opioid Analgesic Involvement in Drug Abuse Deaths in American Metropolitan Areas
Authors: Paulozzi Leonard J.
Published: September 2006

I measured the role of opioid analgesics in drug abuse–related deaths in a consistent panel of 28 metropolitan areas from the Drug Abuse Warning Network. The number of reports of opioid analgesics increased 96.6% from 1997 to 2002; methadone, oxycodone, and unspecified opioid analgesics accounted for 74.3% of the increase. Oxycodone reports increased 727.8% (from 72 to 596 reports). By 2002, opioid analgesics were noted more frequently than were heroin or cocaine. Dramatic increases in the availability of such opioids have made their abuse a major, growing problem.
Detection of Co-Occurring Mental Illness Among Adult Patients in the New Jersey Substance Abuse Treatment System
Authors: Hu Hsou Mei , Kline Anna , Huang Frederick Y. , Ziedonis Douglas M.
Published: September 2006

Objectives. We assessed the detection of mental illness in an adult population of substance abuse patients and the rate of referral for mental health treatment.

Methods. We obtained combined administrative records from 1994 to 1997 provided by the New Jersey substance abuse and mental health systems and estimated detection and referral rates of patients with co-occurring disorders (n = 47 379). Mental illness was considered detected if a diagnosis was in the record and considered undetected if a diagnosis was not in the record but the patient was seen in both treatment systems within the same 12-month period. Predictors of detection and referral were identified.

Results. The detection rate of co-occurring mental illness was 21.9% (n=10364); 57.9% (n=6001) of these individuals were referred for mental health treatment. Methadone maintenance clinics had the lowest detection rate but the highest referral rate. Male, Hispanic, and African American patients, as well as those who used heroin or were in the criminal justice system, had a higher risk of mental illness not being detected. Once detected, African American patients, heroin users, and patients in the criminal justice system were less likely to be referred for treatment.

Conclusions. There is a need to improve the detection of mental illness among substance abuse patients and to provide integrated treatment.
Self-Reported Discrimination and Mental Health Status Among African Descendants, Mexican Americans, and Other Latinos in the New Hampshire REACH 2010 Initiative: The Added Dimension of Immigration
Authors: Gee Gilbert C. , Ryan Andrew , Laflamme David J. , Holt Jeanie
Published: September 2006

Objectives. We examined whether self-reported racial discrimination was associated with mental health status and whether this association varied with race/ethnicity or immigration status.

Methods. We performed secondary analysis of a community intervention conducted in 2002 and 2003 for the New Hampshire Racial and Ethnic Approaches to Community Health 2010 Initiative, surveying African descendants, Mexican Americans, and other Latinos. We assessed mental health status with the Mental Component Summary (MCS12) of the Medical Outcomes Study Short Form 12, and measured discrimination with questions related to respondents’ ability to achieve goals, discomfort/anger at treatment by others, and access to quality health care.

Results. Self-reported discrimination was associated with a lower MCS12 score. Additionally, the strength of the association between self-reported health care discrimination and lower MCS12 score was strongest for African descendants, then Mexican Americans, then other Latinos. These patterns may be explained by differences in how long a respondent has lived in the United States. Furthermore, the association of health care discrimination with lower MCS12 was weaker for recent immigrants.

Conclusions. Discrimination may be an important predictor of poor mental health status among Black and Latino immigrants. Previous findings of decreasing mental health status as immigrants acculturate might partly be related to experiences with racial discrimination.
Incarceration as Forced Migration: Effects on Selected Community Health Outcomes
Authors: Thomas James C. , Torrone Elizabeth
Published: September 2006

Objectives. We estimated the effects of high incarceration rates on rates of sexually transmitted infections and teenage pregnancies.

Methods. We calculated correlations between rates of incarceration in state prisons and county jails and rates of sexually transmitted infections and teenage pregnancies for each of the 100 counties in North Carolina during 1995 to 2002. We also estimated increases in negative health outcomes associated with increases in incarceration rates using negative binomial regression analyses.

Results. Rates of sexually transmitted infections and teenage pregnancies, adjusted for age, race, and poverty distributions by county, consistently increased with increasing incarceration rates. In the most extreme case, teenage pregnancies exhibited an increase of 71.61 per 100000 population (95% confidence interval [CI]=41.88, 101.35) in 1996 after an increase in the prison population rate from 223.31 to 468.58 per 100000 population in 1995.

Conclusions. High rates of incarceration can have the unintended consequence of destabilizing communities and contributing to adverse health outcomes.
Rates and Correlates of Seeking Mental Health Services Among Cambodian Refugees
Authors: Marshall Grant N. , Berthold S. Megan , Schell Terry L. , Elliott Marc N. , Chun Chi-Ah , Hambarsoomians Katrin
Published: September 2006

Objectives. We assessed the rates and correlates of seeking mental health services among a probability sample of Cambodian refugees who needed such services.

Methods. Interviewers conducted face-to-face interviews with a representative sample drawn from the largest US community of Cambodian refugees. The analytic sample included 339 persons who met past 12-month criteria for posttraumatic stress disorder, major depression disorder, or alcohol use disorder. Respondents described contact with service providers for psychological problems during the preceding 12 months. We examined bivariate and multivariate predictors of seeking services.

Results. Respondents reported high rates of contact with both medical care providers (70%) and mental health care providers (46%). Seeking services from both types of providers was associated with lack of English-speaking proficiency, unemployment, 3 or fewer years of preimmigration education, and being retired or disabled. Women, individuals with health insurance, and persons receiving government assistance also were more likely to seek services.

Conclusions. Cambodian refugees with mental health problems had high rates of seeking service for psychological problems during the preceding 12 months. Research is needed to examine the effectiveness of services received by Cambodian refugees.
NovaSure™: The Bipolar Radiofrequency Endometrial Ablation System for Dysfunctional Uterine Bleeding
Authors: Laberge Philippe Y
Published: September 2006

The bipolar radiofrequency endometrial ablation system (NovaSure™) has been developed to treat women suffering from menorrhagia due to dysfunctional uterine bleeding. This technology allows for a customized, controlled, contoured endometrial ablation, without the need for hysteroscopic visualization and endometrial pretreatment. Average treatment time is 90 s. Active bleeding, at the time of treatment, is not found to be a limiting factor for the use of this technology. Technical aspects of the bipolar radiofrequency ablation procedure are described and summarized in this article. The safety features employed, combined with a high level of effectiveness and patient satisfaction, qualifies this system for consideration as a logical alternative to hysterectomy as well as an alternative to hysteroscopic endometrial ablation.
Chemoprevention of Breast Cancer
Authors: Cuzick Jack
Published: September 2006

Trials with tamoxifen have clearly shown that estrogen receptor-positive breast cancer risk can be reduced at a late stage in the natural history with prophylactic agents. Approximately half of the cases were prevented. The current challenge is to achieve this or better efficacy, and to reduce side effects. A recent trial found that the selective estrogen receptor modulator raloxifene has similar efficacy to tamoxifen but fewer side effects. Long-term Phase III trials are currently underway studying two aromatase inhibitors. Results from other studies suggest that these agents have a better side-effect profile and may prevent 70–80% of receptor-positive breast cancers. New agents are needed for receptor-negative breast cancer and several possibilities are currently under investigation.
Semiconductors, Compound
Authors: Koleske Daniel D. , Drummond Timothy J. , Biefeld Robert M. , Sherwin Marc E. , Crawford Mary H.
Published: September 2006

The term compound semiconductor encompasses a large number of materials, most of which crystallize in either the zincblende, wurtzite, or rock salt crystal structures. This article focuses primarily on the properties of the most extensively studied Groups III and V and Groups (2, 12) II–VI compound semiconductors. A summary of the physical (mechanical and electrical) properties of these semiconductors, a description of the metal organic chemical vapor deposition process, the physics and applications of electronic and photonic devices, and the fabrication process technology in use to create both electronic and photonic devices and circuits are discussed.
Spices
Authors: Grenis Anthony T.
Published: September 2006

This article emphasizes the use of spices in flavorings; other applications are known. The use of essential oils, derived from spices by various methods, and oleoresins, derived from spices by extraction, are components of flavor; their applications are included in this section. The quintessence of some spices, the essential oils, are described more fully elsewhere (see
Essential Oils
).

Topics discussed include history of spice and spice trade; labeling; cultivation and production. Processing includes information on the extraction of volatile compounds in spices and control of microbes at harvest. Adulteration is a recent problem. The methods of adulteration and laws involving this problem are detailed. Presentation of source, usage, and flavor characteristics of common individual spices ends the article.
PTCH mutations in four Brazilian patients with holoprosencephaly and in one with holoprosencephaly‐like features and normal MRI
Authors: Ribeiro Lucilene Arilho , Murray Jeffrey C. , Richieri‐Costa Antonio
Published: September 2006

We report five Brazilian probands with PATCHED (PTCH) mutations and highly variable phenotypes with holoprosencephaly in four cases and holoprosencephaly‐like facial features with a normal MRI in a fifth case. Three of our mutations were novel: Ala443Gly, Val751Gly, and Val908Gly. Two patients had the same mutation (Val908Gly), but were phenotypically different: alobar holoprosencephaly, absent nasal septum, and midline cleft lip‐palate in one case, and lobar holoprosencephaly, macrocephaly, hypertelorism, clefting of the nose, severe microphthalmia, and a single maxillary central incisor in the other. One of our patients had a Thr1052Met mutation, holoprosencephaly‐like facial features, and a normal MRI. Ming et al. [(2002); Hum Genet 110:297–301] reported an identical mutation, but with alobar holoprosencephaly. © 2006 Wiley‐Liss, Inc.
Single maxillary central incisor, holoprosencephaly, and holoprosencephaly‐like phenotype
Authors: Richieri‐Costa A. , Ribeiro Lucilene Arilho
Published: September 2006

Three patients—one with alobar holoprosencephaly and two with a holoprosencephaly‐like phenotype—are reported with no identifiable mutations. In each case, one parent had a single maxillary central incisor (SMCI). We briefly review the holoprosencephaly‐like phenotype and present a table of 25 conditions with SMCI. © 2006 Wiley‐Liss, Inc.
Enhanced performance in organic light‐emitting diodes with copolymers containing both tris(8‐hydroxyquinoline) aluminum and 8‐hydroxyquinoline lithium groups
Authors: Du N. Y. , Tian R. Y. , Peng J. B. , Mei Q. B. , Lu M. G.
Published: September 2006

We synthesized novel copolymers containing both tris(8‐hydroxyquinoline) aluminum (Alq3) and 8‐hydroxyquinoline lithium (Liq) groups as emitting layers for use in conventional two‐layer organic light‐emitting diodes. The network structure and thermal stability of these materials is described. The optical and electroluminescent properties of the copolymers were also studied. The performance optimization of the devices with the copolymers through the variation of the ratio of Alq3 to Liq is described. A mechanism responsible for the improved electron injection is put forward. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 4404–4410, 2006
Properties and morphology of bioceramics/poly(D,L‐lactide) composites modified by in situ compatibilizing extrusion
Authors: Liu Fang , Jin Yan , Lin Xiaodan , Jia Demin
Published: September 2006

Composites of poly(D,L‐lactide) (PDLLA) with hydroxylapatite (HA) and PDLLA with tertiary calcium phosphate (TCP) were prepared by in situ modification with methylenediphenyl diisocyanate (MDI) and molded by piston extrusion at temperature between Tg and Tm of PDLLA. Mechanical properties of the composites increased obviously when compared with the unmodified bioactive ceramic particles/PDLLA composites. The effect of MDI contents on mechanical properties of the composites was studied. At the optimum conditions of 1.0/1.0molar ratios of NCO groups in MDI to OH groups in PDLLA, bending strength 68.4 MPa and bending modulus 2281.5 MPa, were achieved in composite HA/PDLLA/MDI with 15 wt % HA. Both increased by nearly 30% when compared with that of solution cast HA/PDLLA composites. Interfacial adhesion and compatibility between PDLLA and bioactive ceramic particles (HA and TCP) were investigated. Scanning electron microscopy (SEM) indicated that the interface between HA particles and PDLLA was blurred and HA particles were closely surrounded by PDLLA matrix in HA/PDLLA/MDI composites. Oriented fibrils along with longitudinal direction of extrusion die were also observed on the surfaces of HA/PDLLA/MDI composite. It is confirmed that MDI has improved interfacial adhesion and compatibility between HA particles and PDLLA phase. Fibril structures formed in the extrusion, and it contributed a great deal in enhancing the mechanical properties. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 4085–4091, 2006
Light‐colored fluorinated polyimides based on 2,5‐bis(4‐amino‐2‐trifluoromethylphenoxy)biphenyl and various aromatic dianhydrides
Authors: Yang Chin‐Ping , Su Yu‐Yang , Chen Yung‐Chung
Published: September 2006

A novel trifluoromethyl‐containing aromatic diamine monomer, 2,5‐bis (4‐amino‐2‐trifluoromethylphenoxy)biphenyl (2), was prepared through the nucleophilic substitution reaction of 2‐chloro‐5‐nitrobenzotrifluoride and phenylhydroquinone in the presence of potassium carbonate to yield the intermediate dinitro compound (1), followed by catalytic reduction with hydrazine and Pd/C. A series of fluorinated polyimides (code 5a–f) were synthesized from diamine (2) with six commercially available aromatic dianhydrides using a standard two‐stage process with thermal or chemical imidization of poly(amic acid). Most of fluorinated polyimides showed good solubility at a concentration of 5–10 wt % and even in pyridine and dioxane. For improving solubility of 5c, copolyimides (5c/a–f) were also prepared from 2 and a pair of dianhydrides (3c/a–f), which were mixed in the molar ratio 1:1. All the polyimide films had a tensile strength in the range from 73 to 112 MPa, an elongation at break within a range of 9–23%, and an initial modulus in the range of 1.6–2.2 GPa. These polyimides exhibited glass transition temperatures of 220–267°C and showed no significant decomposition below 500°C under either nitrogen or air atmosphere. In comparison with the analogous nonfluorinated polyimides based on 2,5‐bis (4‐aminophenoxy) biphenyl (2′), the fluorinated polyimides showed better solubility as well as reduced color intensity, lower dielectric constant, and moisture absorption. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 4101–4110, 2006
Synthesis and properties of organosoluble polyimides derived from bis(4‐amino‐3,5‐dimethyl phenyl) halo phenyl methane and various dianhydrides
Authors: Hariharan R. , Sarojadevi M.
Published: September 2006

A series of organosoluble polyimides with various aromatic tetracarboxylic acid dianhydrides was prepared from diamine monomers using one‐ and two‐step methods. All the polyimides were soluble in aprotic solvents such as NMP, DMF, DMAc, and DMSO. The polyimides showed excellent thermal stability and good mechanical properties. The glass‐transition temperature of the prepared polyimides ranged from 210°C to 325°C. All the polyimides formed tough transparent films, with tensile strength of 84–118 MPa, 8%–12% elongation, and 1.5–2.3 GPa modulus. These polyimide films were found to have a dielectric constant in the range of 3.29–3.80 at 1 kHz and 3.14–3.76 at 10 kHz and low moisture uptake, 0.52%–1.10%. ©2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 4127–4135, 2006
Miniemulsion and conventional emulsion copolymerization of styrene and butadiene: Effect of process on gel content
Authors: Li Donghong , Sudol E. David , El‐Aasser Mohamed S.
Published: September 2006

The properties of styrene/butadiene copolymers obtained by conventional emulsion and miniemulsion polymerizations were studied. Thin layer chromatography with flame ionization detection was used to determine the gel fraction of the copolymer in the latex particles as a function of conversion. It was found that the gel formation began at a higher conversion in the miniemulsion polymerization when compared with that in the conventional process. Also, a lower glass transition temperature was noted at the lowest conversion sampled (∼25%), implying a higher initial butadiene monomer concentration within the nucleated miniemulsion monomer droplets when compared with particles formed conventionally. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 4616–4622, 2006
Effect of aging on synthesis of graft copolymer of EPDM and styrene (EPDM‐g‐PS)
Authors: Wonglert Chalermpol , Thongyai Supakanok , Praserthdam Piyasan
Published: September 2006

The effect of aging on synthesis by the graft copolymerization of styrene onto random ethylene–propylene–diene monomer with benzoyl peroxide (BPO) as the initiator is described. Results showed that yields of graft copolymer are increased in the first 10 min. After 10 min, the total polymer produced has a maximum at about 25 min. However, the portion of the graft copolymer is decreased and the portion of the pure polystyrene is increased. In addition, the influence factors, such as reaction time, temperature, BPO concentrations and styrene concentrations, effect of solvents on the extent of graft copolymerization were discussed. The extent of grafted copolymerization was verified by hexane and acetone Soxhlet (solvent extraction). © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 4809–4813, 2006
Rheological properties of hydrophobically modified polyelectrolyte systems: Concentration effects
Authors: Tam K. C. , Ng W. K. , Jenkins R. D.
Published: September 2006

The behavior of hydrophobically modified alkali‐soluble associative polymer (HASE) at various polymer concentrations was investigated. The results showed that the formation of network structure, which enhances the rheological behavior, depends on two critical polymer concentrations, namely the critical cluster overlapping concentration (C*) and the established network concentration (C**). C* is defined as the critical concentration for the transformation of individual cluster to a transient network structure. C** represents the critical concentration in the semidilute regime where the formation of transient network is completely established. Experimental results demonstrated that the polymer solutions transformed from a predominantly viscous behavior below C* to one with dominant elastic properties above C**. Because of the formation of larger aggregation number above C**, the relaxation times of the polymer systems shift to longer times. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 5166–5173, 2006
Effect of annealing on poly(urethane‐siloxane) copolymers
Authors: Yeh Jen‐Taut , Shu Yao‐Chi
Published: September 2006

Poly(urethane‐siloxane) copolymers were prepared by copolymerization of OH‐terminated polydimethylsiloxane (PDMS), which was utilized as the soft segment, as well as 4,4′‐diphenylmethane diisocyanate (MDI) and 1,4‐butanediol (1,4‐BD), which were both hard segments. These copolymers exhibited almost complete phase separation between soft and hard segments, giving rise to a very simple material structure in this investigation. The thermal behavior of the amorphous hard segment of the copolymer with 62.3% hard‐segment content was examined by differential scanning calorimetry (DSC). Both the T1 temperature and the magnitude of the T1 endotherm increased linearly with the logarithmic annealing time at an annealing temperature of 100°C. The typical enthalpy of relaxation was attributed to the physical aging of the amorphous hard segment. The T1 endotherm shifted to high temperature until it merged with the T2 endotherm as the annealing temperature increased. Following annealing at 170°C for various periods, the DSC curves presented two endothermic regions. The first endotherm assigned as T2 was the result of the enthalpy relaxation of the hard segment. The second endothermic peak (T3) was caused by the hard‐segment crystal. The exothermic curves at an annealing temperature of above 150°C exhibited an exotherm caused by the T3 microcrystalline growth. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102:5174–5183, 2006
Green strength enhancement in BIIR/Olefin copolymer compounds
Authors: Tsou Andy H. , Duvdevani Ilan , Datta Sudhin
Published: September 2006

Improved green strength of halobutyl at elevated temperatures was obtained via blending with semicrystalline polymers. For such improvement, a judicious selection of olefin copolymers, such as ethylene–propylene, ethylene–butene, or ethylene–octene copolymers, as blend components has to be made. Green strength enhancement was found to increase with increasing compatibility between bromobutyl (BIIR) and the olefin copolymer. Increased compatibility may be estimated by chain dimension similarity in a dilute solution between polyisobutylene and the olefin copolymer. For the most compatible olefin copolymer examined, a propylene elastomer, a phase percolation threshold was found at 0.13 volume fraction of the copolymer. This threshold value is lower than the theoretical limit of 0.156 for spherical phase domains. Based on the morphological examination by tapping phase AFM, it was found that this propylene elastomer crystallizes around the carbon black filler agglomerates to form nonspherical and high‐aspect‐ratio dispersed phases. Its phase anisotropy may contribute to its lower phase percolation threshold in BIIR compounds. Model innerliner compounds of BIIR containing 10–20 phr of such a propylene elastomer in place of natural rubber were shown to have excellent room‐temperature and improved elevated‐temperature green strengths, good aging resistance, and excellent impermeability without significant increases in relaxation time. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 4447–4459, 2006
Synthesis and characterization of poly(ethylene glycol dimethacrylate–1‐vinyl‐1,2,4‐triazole) copolymer beads for heavy‐metal removal
Authors: Uzun Lokman , Kara Ali , Tüzmen Nalan , Karabakan Abdülkerim , Beşirli Necati , Denizli Adil
Published: September 2006

We prepared poly(ethylene glycol dimethacrylate–1‐vinyl‐1,2,4‐triazole) [poly(EGDMA–VTAZ)] beads (average diameter = 150–200 μm) by copolymerizing ethylene glycol dimethacrylate (EGDMA) with 1‐vinyl‐1,2,4‐triazole (VTAZ). The copolymer composition was characterized by elemental analysis and found to contain five EGDMA monomer units for each VTAZ monomer unit. The poly(EGDMA–VTAZ) beads had a specific surface area of 65.8 m2/g. Poly(EGDMA–VTAZ) beads were characterized by Fourier transform infrared spectroscopy, elemental analysis, surface area measurements, swelling studies, and scanning electron microscopy. Poly(EGDMA–VTAZ) beads with a swelling ratio of 84% were used for the heavy‐metal removal studies. The adsorption capacities of the beads for Cd(II), Hg(II), and Pb(II) were investigated in aqueous media containing different amounts of these ions (5–750 mg/L) and at different pH values (3.0–7.0). The maximum adsorption capacities of the poly(EGDMA–VTAZ) beads were 85.7 mg/g (0.76 mmol/g) for Cd(II), 134.9 mg/g (0.65 mmol/g) for Pb(II), and 186.5 mg/g (0.93 mmol/g) for Hg(II). The affinity order toward triazole groups on a molar basis was observed as follows: Hg(II) > Cd(II) > Pb(II). pH significantly affected the adsorption capacity of the VTAZ‐incorporated beads. The equilibrium data were well fitted to the Redlich–Peterson isotherm. Consideration of the kinetic data suggested that chemisorption processes could have been the rate‐limiting step in the adsorption process. Regeneration of the chelating‐beads was easily performed with 0.1M HNO3. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 4276–4283, 2006
Curing behavior and thermal mechanical properties of cyanate ester blends
Authors: Koh Henry C. Y. , Dai Jie , Tan Eileen
Published: September 2006

Cyanate esters are a class of important thermally resistant polymers. To tailor their processability and thermomechanical properties, a series of cyanate ester blends based on a trifunctional novolac cyanate ester (HF‐5), a difunctional bisphenol E cyanate ester (HF‐9), and a reactive catalyst [2,2′‐diallyl bisphenol A (DBA)] were formulated. The effect of the blend composition on the rheology and curing behavior of these cyanate ester blends and the corresponding thermal and mechanical properties of the cured cyanate ester blends was studied. The results showed that HF‐5 contributed to good mechanical property retention at high temperatures because of its trifunctionality, whereas HF‐9 imparted processability by reducing the viscosity and extending the pot life of the formulated cyanate ester blends at the processing temperature. On the basis of the results, an optimal cyanate ester blend suitable for resin transfer molding was determined: the HF‐5/HF‐9/DBA weight ratio of 80 : 15 : 5 exhibited good processability and thermomechanical properties. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 4284–4290, 2006
Optimization of synthetic conditions of a novel collagen‐based superabsorbent hydrogel by Taguchi method and investigation of its metal ions adsorption
Authors: Pourjavadi A. , Salimi H. , Amini‐Fazl M. S. , Kurdtabar M. , Amini‐Fazl A. R.
Published: September 2006

A novel biopolymer‐based superabsorbent hydrogel was synthesized through chemical crosslinking by graft copolymerization of partially neutralized acrylic acid onto the hydrolyzed collagen, in the presence of a crosslinking agent and a free radical initiator. The Taguchi method, a robust experimental design, was employed for the optimization of the synthesis reaction based on the swelling capacity of the hydrogels. This method was applied for the experiments and standard L16 orthogonal array with three factors and four levels were chosen. The critical parameters that have been selected for this study are crosslinker (N,N′‐methylene bisacrylamide), initiator (potassium persulfate), and monomer (acrylic acid) concentration. From the analysis of variance of the test results, the most effective factor to control equilibrium swelling capacity was obtained and maximum water absorbency of the optimized final product was found to be 500 g/g. The surface morphology of the gel was examined using scanning electron microscopy. Furthermore, the sorption capacity of the hydrogel toward bivalent metal ions was evaluated. Therefore, the hydrogel may be considered as a candidate to develop as an efficient biopolymer‐based chelating hydrogel for water treatment. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 4878–4885, 2006
Accelerated aging versus realistic aging in aerospace composite materials. I. The chemistry of thermal aging in a low‐temperature‐cure epoxy composite
Authors: Dao B. , Hodgkin J. , Krstina J. , Mardel J. , Tian W.
Published: September 2006

Samples of an aerospace‐grade epoxy composite (M20/IM7) are subject to long‐term (∼ 1 year) thermal aging at temperatures of 70°C, 120°C, 170°C, and 200°C (in air) and the changes to the chemical and physicochemical structure of the composite are analyzed by a range of different techniques, including gravimetric analysis, FTIR, DSC, and DMA to compare the effects of different severities of degradation treatment. The results show that at the lower temperatures, the oxidative degradation changes are very selective for chemical defect groups, particularly near the sample surfaces. However, at the higher temperatures, combinations of further cure reactions and generalized oxidative degradation changes (again from the surface inwards) make for a highly complex ageing pattern for this particular composite material. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 4291–4303, 2006
Weathering, water absorption, and durability of silicon, acetylated, and heat‐treated wood
Authors: Temiz Ali , Terziev Nasko , Jacobsen Bjørn , Eikenes Morten
Published: September 2006

In this study, two colloidal dispersions of pure amorphous silicon dioxide particles, acetylated, and heat‐treated samples were tested for a possible application as a wood protection agents. The silicon, acetylated, and heat‐treated samples were exposed to an accelerated weathering experiment, and their dimensional stability was assessed. The weathering experiment comprised cycles of 2 h UV‐light irradiation followed by water spray for 18 min. The surface changes of the weathered samples were characterized by FT‐IR spectroscopy and color measurements. According to results, the silicon treatments showed lower color changes than untreated ones. However, acetylated and heat‐treated samples provided the lowest color changes. The resistance of the silicon, acetylated, and heat‐treated wood to decay was studied by means of brown and white rot fungi in laboratory decay tests. Decay test results revealed that acetylated and heat‐treated wood samples showed better decay resistance against P. placenta and C. versicolor than silicon treatments. Samples modified with silicon were exposed in above ground standard lap‐joint test in Ultuna, Sweden. The dispersions of pure amorphous silicon dioxide impregnated in wood did not significantly influence its hygroscopic and dimensional behavior. However, the silicon treatment reduced the color changes caused by weathering. The silicon impregnated samples showed a weak fungal discoloration similar to that of chromated copper arsenate impregnated controls in above ground standard lap‐joint test. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 4506–4513, 2006
Waste natural gum as a multifunctional additive in rubber
Authors: Guhathakurta S. , Anandhan S. , Singha Nikhil K. , Chattopadhyay R. N. , Bhowmick Anil K.
Published: September 2006

Bahera gum, extracted from the bark of Terminalia bellerica, is a waste material. The present study involves the use of this natural gum as a multifunctional additive in natural rubber (NR) and brominated isobutylene‐co‐paramethyl styrene (BIMS). Fourier transform infrared (FTIR) analysis was employed to study the functional groups present in the gum. It was found that fatty acids/esters in the gum act as accelerator activator and can replace stearic acid in rubber formulations. Polyphenols in the gum act as antioxidant and the action is comparable with the commercial antioxidant 2,2,4‐trimethyl‐1,2‐dihydroquinoline (TQ) in natural rubber. The gum improves the tack strength of the rubbers (21% at 2.5 phr loading for NR and 54% at 10 phr loading for BIMS). The gum imparts plasticization effect which is reflected in the reduction in k and enhancement in n values, the exponents in the power law equation, with increasing gum concentration. The activation energy of flow is also reduced with the addition of the gum. Moreover, it decreases the elastic memory of the system which causes reduction in die swell. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 4897–4907, 2006
Synthesis and characterization of functional copolymers of citronellol and acrylamide
Authors: Srivastava A. K. , Pandey Prachi , Mishra Garima
Published: September 2006

The radical copolymerization of citronellol with acrylamide in xylene at (80 ± 10)°C for 1 h in the presence of benzoylperoxide follows ideal kinetics with bimolecular termination and results in the formation of an alternating copolymer as evidenced from the values of reactivity ratios as r1 (acrylamide) = 0.0045 and r2 (citronellol) = 0.0005, which have been calculated by Kelen–Tüdos method. The overall activation energy is computed as 44 kJ/mol. The IR spectrum of the copolymer shows the presence of bands at 3427 cm−1 due to alcoholic group and 1710 cm−1 due to amide group. The 1H NMR spectrum of the copolymer shows peaks between 6.3 and 7δ due to amide group (> CO stretching) and between 7 and 7.7δ due to alcoholic group. The values of Mark–Houwink constant for present copolymer system have been evaluated as α = 0.33 and K = 2.3 × 10−1 with the help of gel permeation chromatography. The Alfrey‐price, Q–e parameters for citronellol have been calculated as 0.43 and 1.07. The copolymer is highly thermally stable and has a glass transition temperature (Tg) of 102°C as evaluated from differential scanning calorimetry studies. The mechanism has also been elucidated. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 4908–4914, 2006
Preparation and characterization of polystyrene–poly(ethylene oxide) amphiphilic block copolymers via atom transfer radical polymerization: Potential application as paper coating materials
Authors: Ibrahim Khalid , Salminen Arto , Holappa Susanna , Kataja Kirsi , Lampinen Henna , Löfgren Barbro , Laine Janne , Seppälä Jukka
Published: September 2006

Poly(ethylene oxide) (PEO) monochloro macroinitiators or PEO telechelic macroinitiators (Cl‐PEO‐Cl) were prepared from monohydroxyfunctional or dihydroxyfunctional PEO and 2‐chloro propionyl chloride. These macroinitiators were applied to the atom transfer radical polymerization of styrene (S). The polymerization was carried out in bulk at 140°C and catalyzed by Copper(I) chloride (CuCl) in the presence of 2,2′‐bipyridine (bipy) ligand (CuCl/bipy). The amphiphilic copolymers were either A‐B diblock or A‐B‐A triblock type, where A block is polystyrene (PS) and B block is PEO. The living nature of the polymerizations leads to block copolymers with narrow molecular weight distribution (1.072 < Mw/Mn < 1.392) for most of the macroinitiators synthesized. The macroinitiator itself and the corresponding block copolymers were characterized by FTIR, 1H NMR, and SEC analysis. By adjusting the content of the PEO blocks it was possible to prepare water‐soluble/dispersible block copolymers. The obtained block copolymers were used to control paper surface characteristics by surface treatment with small amount of chemicals. The printability of the treated paper was evaluated with polarity factors, liquid absorption measurements, and felt pen tests. The adsorption of such copolymers at the solid/liquid interface is relevant to the wetting and spreading of liquids on hydrophobic/hydrophilic surfaces. From our study, it is observed that the chain length of the hydrophilic block and the amount of hydrophobic block play an important role in modification of the paper surface. Among all of block copolymers synthesized, the PS‐b‐PEO‐b‐PS containing 10 wt % PS was found to retard water absorption considerably. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 4304–4313, 2006
Microencapsulation of water‐soluble flame retardant containing organophosphorus and its application on fabric
Authors: Lin Miao , Yang Yong , Xi Ping , Chen Shui‐lin
Published: September 2006

Microencapsulation is based on multiple emulsion interfacial reaction technique that combines the characteristics of the interfacial reaction and conventional multiple‐emulsion processes. In this study, the microcapsules were synthesized with the water‐soluble dimethyl methyl phosphorate (DMMP) as the core material and the acetal product of polyvinyl alcohol (PVA) and glutaraldehyde (GA) as the shell material. The microcapsules were characterized by using DSC, IR spectrum and phosphorus qualitative analysis, and the factors affecting microencapsulation were identified and discussed. The data presented herein suggested that the size distribution of microcapsules was affected by the concentration of PVA and SPAN80 and by the phase volume ratio, while the crosslinking agent GA content has little effect. The data also showed that the microcapsules with the core of flame retardant containing organophosphorus would have promising applications in inflaming retarding of cotton fabric. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 4915–4920, 2006
Antimicrobial poly(N‐vinyl‐2‐pyrrolidone‐alt‐maleic anhydride)/poly(ethylene imine) macrocomplexes
Authors: Temiz Ayhan , Özmen Toğay Sine , Şener Ayla , Güven Güldem , Rzaev Zakir M. O. , Piskin Erhan
Published: September 2006

The antimicrobial polymer/polymer macrocomplexes were synthesized by radical alternating copolymerization of N‐vinyl‐2‐pyrrolidone with maleic anhydride [poly(VP‐alt‐MA)] with 2,2′‐azobis‐isobutyronitrile as an initiator at 65°C in dioxane solutions under nitrogen atmosphere, and interaction of prepared copolymer with poly(ethylene imine) (PEI) in aqueous solutions. The susceptibility of some Gram‐negative (Salmonella enteritidis and Escherichia coli) and Gram‐positive (Staphylococcus aureus and Listeria monocytogenes) bacteria to the alternating copolymer and its PEI macrocomplexes with different compositions in microbiological medium was studied using pour‐plate technique. All the studied polymers, containing biologically active moieties in the form of ionized cyclic amide, and macrobranched aliphatic amine groups and acid/amine complexed fragments, were more effective against L. monocytogenes than those for Gram‐positive S. aureus bacterium. This fact was explained by different surface layer structural architectures of biomacromolecules of tested bacteria. The resulting polymeric antimicrobial materials are expected to be used in various areas of medicine and food industry. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102:5841–5847, 2006
Electrorheological properties of chemically modified chitosan suspension with various functional pendants
Authors: Ko Young Gun , Choi Ung Su
Published: September 2006

In this study, functional pendants of chitosan were focused on enhancing the shear stress of electrorheological (ER) fluids. Chitosan succinates and chitosan phthalate were synthesized for ER particles and ER fluids were prepared by dispersing the particles in silicone oil. After comparing the shear stress of all prepared ER fluids, obtained conclusions were that ER particle having two functional groups (one is +ve charge and another is −ve charge) showed higher shear stress than that having only one functional group like the comparison between chitosan succinate(I) and chitosan succinate(II). However, though expect of the intermolecular overlapping between the π electrons clouds supporting the charge carrier generation and transport leading to a significant delocalization of electrons, chitosan phthalate shows lower shear stress than chitosan succinate(I) and chitosan succinate(II). © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 4937–4942, 2006
Structure and properties of PMP foams doped with Cu nanopowders
Authors: Du K. , Zhang L. , Luo X. , Yin Q.
Published: September 2006

Poly‐4‐methyl‐1‐pentene (PMP) foams doped with Cu nanopowders have been prepared by thermally induced phase separation. Ultrasonic dispersal was exploited to increase dispersion uniformity of Cu nanopowders in the foam skeleton. With increase in the concentration of Cu nanopowders, the structure of the doped PMP foams becomes finer and the size of cells, smaller. The modulus data of the doped foams described by a scaling constant larger than two significantly overestimate the predicted value. These indicate two roles of Cu nanopowders in PMP foams: fortifiers of foam structure and nuclei in polymer crystallization. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 5627–5632, 2006
Preparation of novel acrylate‐based liquid crystalline polymers and the photoinduced alignment behavior of their films
Authors: Zhu Jun , Wu Li‐Ping , Zhang Yu‐Ying , Jin Xi , He Shang‐Jin , Shi Ke‐Yu , Guo XianZhi , Du Zong‐Jie , Zhang Bao‐Long
Published: September 2006

Two acrylate monomers containing both mesogenic biphenyl group and photoreactive cinnamoyl group as well as different length of flexible spacers (i.e., n‐[4′‐(n‐cinnamoyloxyalkoxy)biphenyl‐4‐yloxy]alkyl acrylate, n = 4 (A4OO4C) and 6 (A6OO6C)) were synthesized for the first time. Their corresponding polymers (i.e., PA4OO4C and PA6OO6C) were obtained by free radical polymerization using AIBN as an initiator. The monomer A4OO4C showed smectic liquid crystalline phase and a clear fan texture was observed under optical polarizing microscope. However, no liquid crystalline phase was found for A6OO6C. In contrast, PA4OO4C showed no liquid crystalline phase while PA6OO6C showed a clear nematic schlieren texture during the cooling process. The optical polarized microscope of E5 cast on the top of the polymer film also showed the alignment. Furthermore, the irradiation of the polymer films by LP‐UV light led to the cycloaddition of the cinnamoyl groups, resulting in the simultaneous alignment of the biphenyl groups. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 4565–4572, 2006
Optical properties of MEH‐PPV conjugated polymer covered by silica nanoshells
Authors: Sáfar G. A. M. , Oliveira F. A. C. , Cury L. A. , Righi A. , Barbosa P. L. M. , Dieudonné P. , Lameiras F. S.
Published: September 2006

Poly [2‐methoxy‐5‐(2′‐ethyl‐hexyloxy)‐1,4‐phenylene vinylene] (MEH‐PPV) covered by nanostructured silica shells were synthesized via sol–gel process and investigated after freeze‐drying and heat‐drying in vacuum. The freeze‐dried sample consists of a light pink powder while the heat‐dried sample presents a redder coarse‐grained material. The freeze‐dried sample was analyzed using small angle X‐ray scattering (SAXS). Both samples were analyzed using photoluminescence (PL) and Raman spectroscopy at room temperature. The PL spectra presented relatively large red shifts compared with that of the MEH‐PPV in tetrahydrofuran solution, which was taken as a reference sample. The energy shifts observed in the PL and Raman spectra strongly support an explanation based on denser packing conditions inside the nanostructured silica shells, which can effectively lead the polymer molecules to a higher interchain interaction via aggregate sites. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 5620–5626, 2006
Dispersion copolymerization of acrylonitrile‐vinyl acetate in supercritical carbon dioxide
Authors: Yang Yajun , Dong Qingzhi , Wang Zi , Shen Cuihui , Huang Zhengfeng , Zhu Hui , Liu Tao , Hu Chun Pu
Published: September 2006

Dispersion copolymerization of acrylonitrile‐vinyl acetate (AN‐VAc) had been successfully performed in supercritical carbon dioxide (ScCO2) with 2,2‐azobisisobutyronitrile (AIBN) as a initiator and a series of lipophilic/CO2‐philic diblock copolymers, such as poly(styrene‐r‐acrylonitrile)‐b‐poly(1,1,2,2‐tetrahydroperfluorooctyl methacrylate) (PSAN‐b‐PFOMA), as steric stabilizers. In dispersion copolymerization, poly(acrylonitrile‐r‐vinyl acetate) (PAVAc) was emulsified in ScCO2 effectively using PSAN‐b‐PFOMA as a stabilizer. Compared with the precipitation polymerization (absence of stabilizer), the products prepared by dispersion polymerization possessed of higher yield and higher molecular weight. In addition, the particle morphology of precipitation polymerization was irregular, but the particle morphology of dispersion polymerization was uniform spherical particles. In this study, the effects of the initial concentrations of monomer and the stabilizer and the initiator, and the reaction pressure on the yield and the molecular weight and the resulting size and particle morphology of the colloidal particles were investigated. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 5640–5648, 2006
Influence of alkali treatment on the fine structure and morphology of bamboo fibers
Authors: Das Mahuya , Chakraborty Debabrata
Published: September 2006

Bamboo fibers in the form of strips and dust were treated with NaOH solution of varying concentration (10, 15, and 20%). These treated and untreated samples were then subjected to FTIR and morphological studies. Again XRD study was carried out on those treated and untreated bamboo samples in both strip and dust form. It was found that during alkali treatment a lattice transformation from cellulose‐I to cellulose‐II took place. It is observed from IR index value that the conversion is maximum in between 15 and 20% of alkali treatment. Swelling in NaOH introduces considerable changes in crystallinity, orientation angle, etc. Degree of crystallinity and crystallinity index for bamboo strips increases with increasing treatment concentration of alkali and falls off after 15% alkali concentration. This is also supported by d‐spacing value. Orientation factor fx was calculated from the FWHM and it was found that fx value has been increased from 0.9879 to 0.9915 for 15% alkali treated and again lowered to 0.8522 for 50% alkali treated samples. Same observation of X‐ray study was obtained for dust samples but at an earlier concentration. Morphological study of bamboo dust with scanning electron microscope indicates fibrillation at higher alkali concentration. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 5050–5056, 2006