bluuebunny/crossref_metadata_2025_split huggingface dataset:
Graft copolymerization of acrylamide onto cellulose in presence of comonomer using ceric ammonium nitrate as initiator
Authors: Gupta K. C. , Khandekar Keerti 
Published: May 2006

AbstractThe graft copolymerization of acrylamide (AAm) and ethylmethacrylate (EMA) monomers onto cellulose has been carried out using ceric ammonium nitrate (CAN) as initiator in presence of nitric acid at (25 ± 1)°C and varying feed molarity from 7.5 × 10−2 mol dm−3 to 60.0 × 10−2 mol dm−3 at fixed feed composition (fAAm = 0.6). The graft yield (%GY) has shown a linear increasing trend upto a feed molarity of 37.5 × 10−2 mol dm−3. The composition of grafted copolymer chains was found to be constant (FAAm = 0.56) during feed molarity variation but shown variations with feed composition (fAAm) and reaction temperature. The grafting parameters have shown increasing trends up to 7.5 × 10−3 mol dm−3 concentration of ceric (IV) ions and decreased on further increasing the concentration of ceric (IV) ions beyond 7.5 × 10−3 mol dm−3. The IR and elemental analysis data were used to determine the composition of grafted chains (FAAm) and reactivity ratio of acrylamide (r1) and ethylmethacrylate (r2) comonomers. The reactivity ratio for acrylamide (r1) and ethylmethacrylate (r2) has been found to be 0.7 and 1.0 respectively, which suggested for an alternate arrangement of average sequence length of acrylamide (mM̄1) and ethylmethacrylate (mM̄2) in grafted chains. The rate of graft copolymerization of comonomers onto cellulose was found to be proportional to square concentration of comonomers and square root to the concentration of ceric (IV) ions. The energy of activation (ΔEa) of graft copolymerization was found to be 9.57 kJ mol−1 within the temperature range of 20–50°C. On the basis of experimental findings, suitable reaction steps have been proposed for graft copolymerization of selected comonomers. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 2546–2558, 2006
Composites of high density polyethylene and different grades of calcium carbonate: Mechanical, rheological, thermal, and morphological properties
Authors: Teixeira Sylvia C. S. , M. Moreira Maria , Lima Aline P. , Santos Luciene S. , da Rocha Bianca M. , de Lima Edson S. , da Costa Raphael A. A. F. , da Silva Ana Lúcia N. , Rocha Marisa C. G. , Coutinho Fernanda M. B. 
Published: May 2006

AbstractCalcium carbonate (CaCO3)/high density polyethylene (HDPE) composites were prepared in a HAAKE twin screw extruder, using the experimental conditions defined by the factorial experimental design presented in a prior study. In this study, the effect of different grades (Ca1 and Ca2) and CaCO3 content (varying from 0 to 15 wt %) on the mechanical, rheological, thermal, and morphological properties was evaluated. The results showed that the addition of the filler provoked a decrease on the impact strength, stress at break, and yield stress properties in relation to the pure HDPE. A consequent increase on the modulus of elasticity, indicating an increase on the rigidity of the composite, was observed. It was also verified a tendency to increase the toughness and the viscosity of the composites as CaCO3 was added. Scanning electron micrographs showed that as the filler was incorporated to HDPE matrix, CaCO3 particles tended to agglomerate, especially that grade constituted of particles of smaller size. The thermal analysis showed that the addition of mineral filler caused a decrease on the crystallinity degree. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 2559–2564, 2006
Elastomers based on α,ω‐dihydroxy‐polydimethylsiloxane/polystyrene blends: Morphology and mechanical properties
Authors: Dong Jian , Liu Zonglin , Cao Xiaoqun , Zhang Changjun 
Published: May 2006

Abstractα,ω‐Dihydroxy‐polydimethylsiloxane/polystyrene (PDMS/PS) blends were prepared by the bulk polymerization of styrene (St) in the presence of α,ω‐dihydroxy‐polydimethylsiloxane (PDMS), using benzoyl peroxide (BPO) as initiator. The PDMS/PS blends obtained by this method are a series of stable, white gums, which were vulcanized to elastomers at room temperature with methyl‐triethoxysilicane (MTES). The MTES dosage was much larger than the amount necessary for end‐linking hydroxy‐terminated chains of PDMS, with the excess being hydrolyzed to crosslinked networks, which were similar to SiO2 and acted as filler. Investigations were carried out on the elastomeric materials by extraction measurement and scanning electron microscopy. The extraction data show that at each composition the sol‐fraction is less than expected. Scanning electron microscopy observation demonstrates that the elastomer has microphase‐separated structure consisting of PS domains within a continuous PDMS matrix, and the extracted material exhibits a porous structure. Moreover, the mechanical properties of the elastomers were studied in detail. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 2565–2572, 2006
Nanosized silica‐supported metallocene/MAO catalyst for propylene polymerization
Authors: Li Kuo‐Tseng , Kao Yi‐Tyng 
Published: May 2006

AbstractA nanosized silica particle was used as the support to prepare an Et[Ind]2ZrCl2/MAO catalyst for propylene polymerization of polypropylene. The catalyst and the polymer produced were characterized with nitrogen adsorption, ICP, DSC, SEM, TEM, XRD, solution viscometer, 13C NMR and optical microscopy. The effects of polymerization temperature and [Al]/[Zr] ratio on catalyst activity and polymer melting point were investigated. Under identical reaction conditions, nanosized catalyst exhibited better polymerization activity than the microsized catalyst (e.g., the former had 64% higher activity than the latter at the optimum polymerization temperature (50°C) and [Al]/[Zr] = 570). DSC results indicated that polymer melting point increased with the increase of [Al]/[Zr] ratio and with the decrease of polymerization temperature. XRD results showed that the percentage of γ crystals increased with decreasing [Al]/[Zr] ratio. Electron microscopic results showed that the polymer particle size increased with increasing polymerization temperature. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 2573–2580, 2006
Effect of gamma irradiation on the interpenetrating networks of gelatin and polyacrylonitrile: Aspect of crosslinking using microhardness and crosslink density measurements
Authors: Rajvaidya Sangita , Bajpai R. , Bajpai A. K. 
Published: May 2006

AbstractThe present article reports the effect of gamma irradiation on the hardness behavior of the interpenetrating polymer networks (IPNs) of gelatin and polyacrylonitrile (PAN). Various compositions of gluteraldehyde‐crosslinked gelatin and N, N′‐methylene bis acrylamide (MBA)‐crosslinked PAN were prepared and investigated for microhardness studies. The pre‐ and post‐irradiated IPNs were characterized for their crosslinking density, determined with swelling ratio measurements. It was found that the crosslinked IPNs get further hardened because of radiational hardening at specific doses in the range from 2 to 250 kGy. The role of acrylonitrile and crosslinker (MBA) in the IPNs, as a consequence of irradiation, has also been explained. A fair consistency has been observed between the microhardness results and crosslinking density measurements. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 2581–2586, 2006
Effects of redox initiator on graft copolymerization of methyl methacrylate onto natural rubber
Authors: Kochthongrasamee Teeranuch , Prasassarakich Pattarapan , Kiatkamjornwong Suda 
Published: May 2006

AbstractEffects of cumene hydroperoxide (CHPO)/tetraethylene pentamine (TEPA), tert‐butyl hydroperoxide (TBHPO)/TEPA, and potassium persulfate (K2S2O8)/sodium thiosulfate (Na2S2O3) redox initiator on methyl methacrylate (MMA) grafted natural rubber by emulsion polymerization were investigated. The optimum reaction condition for each redox initiator on the grafting of natural rubber was studied. The grafted poly(methyl methacrylate) (PMMA) stays on the surface of rubber particles. CHPO dissolves very well in the oil phase and TBHPO dissolves moderately in the oil phase, and K2S2O8 /Na2S2O3 initiation is water‐soluble. Each can interact with TEPA in the aqueous phase. CHPO was found to give a higher grafting efficiency. To promote a greater grafting efficiency and yield a lower homopolymer content of PMMA, vinyl neo‐decanoate (VneoD) was added. Percentages of grafting of MMA on natural rubber latex initiated by CHPO/TEPA, TBHPO/TEPA, and K2S2O8/K2S2O3 of 84.4, 74.5, and 61.1, respectively, were in good agreement with percentages of PMMA in the aqueous phase as 7.2, 12.0, and 17.9 by CHPO, TBHPO, and K2S2O8. VneoD produces allylic radicals on polyisoprene chains, favoring the grafting reaction with other vinyl monomers. CHPO/TEPA is thus a better redox system for grafting of MMA monomer on natural rubber latex. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 2587–2601, 2006
Studies on CoSalen immobilized onto N‐(4‐methylimidazole)‐chitosan
Authors: Hu Daodao , Fang Yu , Gao Gailing , Wang Mingzhen 
Published: May 2006

AbstractA chitosan (CS) derivative, N‐(4‐methylimidazole)‐chitosan (MIC), was synthesized, and a cobalt (II) complex of bis(salicylideneethylene diamine), (CoSalen), was immobilized on it. The structure of the polymer‐immobilized CoSalen was characterized by elemental analysis, IR, XPS, fluorescence and ESR spectroscopy. It was demonstrated that the immobilization of CoSalen was realized through the coordination of a nitrogen atom of the pendant group, imidazole in MIC, to the Co(II) in CoSalen. The immobilized polymer complex is more efficient than the corresponding monomeric complex in catalyzing the oxidation of DOPA using oxygen. The results may be attributed to a site isolation effect offered by the supporting polymer chain. A mechanism similar to that for enzymatic catalysis was proposed. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 2431–2436, 2006
Study of poly(vinyl chloride) blends with solid‐state chlorinated polyethylene
Authors: Stoeva S. 
Published: May 2006

AbstractThe influence of solid‐state chlorinated polyethylene of various chlorine content and residual crystallinity on the mechanical properties of rigid poly(vinyl chloride) has been studied. The impact strength of poly(vinyl chloride) was found to increase significantly as 10–20 mass% chlorinated polyethylene, containing from 10.2 to 27.3% chlorine content (preferably 21.8% Cl) were added. This dependence corresponded to the higher elasticity and impact strength of the solid‐state chlorinated polyethylene with chlorine content below 30% as well as the microstructure of its chlorinated block fragments. Multicomponent system of high impact strength and good flowability, consisting of poly(vinyl chloride), chlorinated polyethylene, hydroxyl‐terminated polybutadiene, and ethylene–propylene–ethylidenenorbornene terpolymer was also obtained. Regardless of the incompatibility between the polymer components of this blend, the similarity in the chemical nature of poly(vinyl chloride) and chlorinated polyethylene blocks on one hand, and the methylene sequences in the chlorinated polyethylene and elastomers on the other, resulted in the formation of an efficient interfacial layer. The changes in the structure of the blends were established by both calorimetric and microscopic studies. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 2602–2613, 2006
Supercritical carbon dioxide assisted grafting of polyacrylamide to polypropylene
Authors: Xu Qun , Hou Zhenzhong , Zhang Guangfa , Fan Haijuan , Li Jianbo , Zheng Shijun 
Published: May 2006

AbstractThe grafting of polyacrylamide to polypropylene was realized with supercritical carbon dioxide as a substrate‐swelling agent and monomer/initiator carrier. The effects of supercritical carbon dioxide assisted impregnation and graft polymerization conditions on the grafting ratio were studied. The original polypropylene and grafting products were characterized with infrared spectroscopy, differential scanning calorimetry, and scanning electron microscopy. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 2614–2618, 2006
The radiation effect on thermal conductivity of high strength ultra‐high‐molecular‐weight polyethylene fiber by γ‐rays
Authors: Yamanaka Atsuhiko , Izumi Yoshinobu , Kitagawa Tooru , Terada Takaya , Sugihara Hideki , Hirahata Hiroshi , Ema Kimiko , Fujishiro Hiroyuki , Nishijima Shigehiro 
Published: May 2006

AbstractTo understand the contribution to thermal conductivity by the length of the molecular chains in high strength ultra‐high‐molecular‐weight polyethylene (UHMW‐PE) fiber, the thermal conductivity in the range of low temperature was investigated for high‐strength UHMW‐PE fiber (Toyobo, Dyneema®; hereinafter abbreviated to DF) irradiated by γ‐rays (γ‐rays treatment) that induce the molecular chains scission. The molecular weight of DF decreased by γ‐rays treatment. X‐ray diffraction behavior did not change by γ‐rays treatment. The melting behavior observed by differential scanning calorimetry showed the main chain scission of DF by γ‐rays treatment. Heat capacity decreased slightly by γ‐rays treatment. Thermal conductivities of DF with and without γ‐rays treatment decreased by decreasing temperature. Thermal conductivity of DF decreased very much by γ‐rays treatment. The decrease of thermal conductivity was explained by molecular chain scission in DF by γ‐rays treatment and it suggested the possibility of the reduction of mean free path of phonon. The decreasing rates of thermal conductivity by γ‐rays treatment were smaller than those of molecular weight. Those differences were explained by the difference of probability of chain scission between the amorphous and crystal region. Those results suggested the contribution of the length of extended molecular chains because of high molecular weight on the thermal conductivity of DF. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 2619–2626, 2006
Unsaturated ester resins
Authors: Penczek Piotr , Sodhi Jagolip , Ostrysz Ryszard 
Published: May 2006

AbstractVinyl ester resins (VERs) are often described as a cross between unsaturated polyester resins and epoxy resins. VERs offer an upgrade to epoxy resins, and they tend to be selected when chemical and temperature resistance is required. This research was aimed at developing the synthesis of unsaturated ester resins (UERs), which are similar to VERs. UERs were synthesized by the addition of dihydrodicyclopentadienyl hydrogen maleate to the terminal epoxy groups in low‐molecular‐weight bisphenol A/epichlorohydrin epoxy resins. The effect of urethanization of UERs on the properties of the crosslinked polymer was also investigated. As crosslinking monomers, styrene and glycol dimethacrylates were used. The following properties of cured UERs were determined: the heat deflection temperature, alkali resistance, and the mechanical strength. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 2627–2631, 2006
Improvement in adhesive‐free adhesion by the use of electrostatic interactions between polymer chains grafted onto polyethylene plates
Authors: Kojima Akihiro , Yamada Kazunori , Fujii Takayoshi , Hirata Mitsuo 
Published: May 2006

AbstractThe tensile shear adhesive‐free adhesion properties induced by electrostatic interactions between poly(acrylic acid) (PAA) and poly[2‐(dimethylamino)ethyl methacrylate] (PDMAEMA) chains grafted onto polyethylene (PE) with low‐density (LDPE) or high‐density (HDPE) plates were studied. PAA‐ or PDMAEMA‐grafted PE plates were immersed in a HCl or NaOH solution or water for 24 h, and their electrostatic properties were changed before they were overlapped with each other and heat‐pressed. The breaking of the substrate between the two plates with water‐swollen grafted layers was observed in the low range of grafted amounts in comparison with immersion in the acidic and basic solutions. The ability of the two plates with grafted polymer chains swollen in water to strongly bond with each other was a result of electrostatic interactions formed by positively charged PDMAEMA and negatively charged PAA chains. The breaking of the substrate in the case of adhesive‐free adhesion between quaternized PDMAEMA‐grafted and PAA‐grafted PE plates immersed in the basic solution occurred with lower grafted amounts of PAA. This came from the strong attractive force between dissociated anionic PAA chains and quaternized cationic PDMAEMA chains in the basic solution. In addition, the adhesive‐free adhesion strength of HDPE plates with the same grafted polymer chains encountered the breaking of the substrate with lower grafted amounts than that of LDPE plates. It was concluded that the grafting of polymer chains onto HDPE plates with high crystallinity was considerably restricted to the outer surface regions. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 2632–2638, 2006
Correlation of 13C‐NMR analysis with fungal decay tests of polymeric structural wood constituents. I. Basidiomycetes
Authors: Boonstra M. J. , Pizzi A. , Rigolet S. 
Published: May 2006

AbstractHeat treatment at relatively high temperatures (from 150 to 260°C) is an effective method to improve the durability of wood. This study investigates the reasons for the decay resistance of heat‐treated and nontreated wood with respect to the polymeric structural constituents by solid‐state cross‐polarization/magic‐angle spinning (CP–MAS) 13C‐NMR analysis before and after exposure to brown rot and white rot fungi. An industrial two‐stage heat‐treatment method under relatively mild conditions (<200°C) has been used to treat the samples. Brown rot fungi attack polymeric carbohydrates of nontreated Scots pine sapwood at C4, resulting in cleavage and eventually depolymerization of cellulose and hemicelluloses. The attack at the carbohydrate C6, which has never been observed before, is remarkable because the C6 CH2OH group has no covalent structural function but acts in fixing the three‐dimensional carbohydrate configuration just by secondary forces. The CH2OH group carries OH, which forms some of the strongest hydrogen bonds in the structure of the crystalline native cellulose. It is suggested that the fungus tries to cleave this group to open the cellulose crystalline structure into an amorphous structure to decrease its water repellency to facilitate enzymatic cellulose degradation. Considerable degradation of the hemicelluloses occurs during brown rot fungal exposure, whereas in general the attack on lignin is rather limited, being mainly demethoxylation. However, Gloeophyllum trabeum is an active brown rot fungus in the (partial) degradation of lignin because there is some indication of ring opening of the aromatic ring of lignin during fungal exposure. Aromatic ring opening has also been observed after exposure to Coriolus versicolor, a white rot fungus. The demethoxylation of lignin and some attack on wood carbohydrates are also characteristic of the attack of this white rot fungus. The CP–MAS 13C‐NMR spectra of heat‐treated Norway spruce reveal similarities but also clear differences after fungal exposure in comparison with nontreated Scots pine sapwood. Brown rot fungi seem to have a preference to attack the carbohydrates of heat‐treated wood at C4 and especially C1, cleaving the skeleton of cellulose and glucomannans. In untreated Scots pine sapwood, this attack mainly occurs at C4, the nonreducing end of the glucose unit. An attack on the out‐of‐the‐ring alcoholic group CH2OH of the carbohydrates of heat‐treated Norway spruce is less obvious than that in untreated Scots pine. The attack on C3/C5 of the carbohydrates is remarkable, indicating ring opening of the glucose units, which has not been observed in nontreated Scots pine sapwood. Lignin degradation is limited to demethoxylation, and low or no aromatic ring opening is observed, even after C. versicolor exposure. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 2639–2649, 2006
The morphological structures of net‐modified cotton cellulose with triazine derivative containing multireactive groups
Authors: Xie Kongliang , Hou Aiqin , Sun Yan 
Published: May 2006

AbstractCotton fabric was chemically modified with a 1,3,5‐triazine derivative containing multireactive and multicationic groups, 2,4,6‐tri[(2‐hydroxy‐3‐trimethyl‐ammonium)propyl]‐1,3,5‐triazine chloride (Tri‐HTAC). The morphological structures of net‐modified cotton cellulose were investigated with differential scanning calorimetry, X‐ray diffraction, and scanning electron microscopy. The results showed that crystallinity and preferred orientation of net‐modified cellulose decreased. The tensile strength of net‐modified cotton decreased and crease recovery angle increased. The thermal stability of the net‐modified cotton was slightly improved. Representative scanning electron micrographs indicated that there appears to be appreciable difference in the appearance of the surfaces of the unmodified and the net‐modified cotton fibers. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 2700–2707, 2006
Health status, activity limitations, and disability in work and housework among Latinos and non‐Latinos with arthritis: An analysis of national data
Authors: Abraído‐lanza Ana F. , White Kellee , Armbrister Adria N. , Link Bruce G. 
Published: June 2006

AbstractObjectiveTo document disparities in health status, activity limitations, and disability in work and housework between Latinos and non‐Latino whites with arthritis. We examined whether sociodemographic factors (age, income, and education) account for the disparities between the ethnic groups, and whether comorbid conditions, disease duration, health care utilization, and functional abilities predict health status, activity limitations, and work and housework disability after controlling for sociodemographic variables.MethodsWe analyzed data from the Condition file of the 1994 National Health Interview Survey on Disability, Phase I.ResultsThe risk of worse health, activity limitations, and work and housework disability was >2 times greater among Latinos compared with non‐Latino whites. In the regression models accounting for potential confounders, Latino ethnicity remained significantly associated with poorer health status, but not activity limitations or disability in work or housekeeping. Of the socioeconomic status variables, education had a significant protective effect on work disability and health status. Comorbid conditions and health care utilization increased the likelihood of worse health, activity limitations, and work disability. Limitations in physical function were associated with poorer health and disability in work and homemaking.ConclusionSocial status differences between Latinos and non‐Latinos may account for disparities in activity limitations and disability in work and housework. Education may provide various health benefits, including access to a range of occupations that do not require physical demands. The findings help to address the great gap in knowledge concerning factors related to the health and disability status of Latinos with arthritis.