bluuebunny/crossref_metadata_2025_split huggingface dataset:
Crystallization behaviors of polypropylene and functional polypropylene
Authors: Guan Yong , Wang Shuzhong , Zheng Anna , Xiao Huining 
Published: February 2003

AbstractThe crystallization behaviors of polypropylene (PP) homopolymer and its blends with 0–15% functional polypropylene (FPP), the backbones of which were grafted with guanidine and diamide polymer chains, were investigated with differential scanning calorimetry and wide‐angle X‐ray scattering. The crystallization kinetics were studied with spectral depolarization. The results revealed that the presence of FPP reduced the crystallinity and crystallite size of PP. Meanwhile, FPP increased the crystallization rate. Compared with that of the PP homopolymer, the crystallization temperature of PP/FPP blends was increased by more than 10°C. During isothermal crystallization, the relative crystallinity, developed as a function of time, was described by the Avrami equation. The half‐time of crystallization for PP/FPP blends was much shorter than that for the PP homopolymer. The half‐time of crystallization of PP/FPP blends depended much less on the crystallization temperature than that of the PP homopolymer. Therefore, FPP accelerated the crystallization rate of PP in a manner similar to that of a nucleator. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 872–877, 2003
One‐pot curing system of epoxy resin imines initiated with water
Authors: Suzuki Kentarou , Matsu‐ura Nobuki , Horii Hisakazu , Sugita Yuko , Sanda Fumio , Endo Takeshi 
Published: February 2003

AbstractThe curing and adhesive properties of one‐component epoxy resins containing Epikote 828 and diimines, derived from N,N′‐di(1‐ethylpropylidene)‐m‐xylylenediamine, N,N′‐di(1‐ethylpropylidene)‐1,3‐diaminomethylcyclohexane (2), and N,N′‐di(1,3‐dimethylbutylidene)‐m‐xylylenediamine, which were used as water‐initiated hardeners, were examined. Diethyl ketone‐based imines with a lower electron density on the CN carbon were efficiently hydrolyzed and showed curing activity. 2, a novel diethyl ketone‐based diimine, served as an efficient latent hardener of the epoxy resin. A paste of the epoxy resin with 2 showed good storage stability at room temperature and good adhesive properties. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 878–882, 2003
Dynamic mechanical analysis of particulate‐filled epoxy resin
Authors: Goyanes S. N. , König P. G. , Marconi J. D. 
Published: February 2003

AbstractThe dynamic mechanical properties of epoxy composites filled with different amounts of quartz powder were investigated. The storage modulus and loss tangent were measured at frequencies between 7.8 and 323 Hz from room temperature up to 460 K. The influence of the filler content on the temperature and frequency behavior of the dynamic mechanical properties is discussed and explained in terms of models presented in the literature. In particular, the dependence of the composite damping with the quartz content is explained with regard to damping due to particle–particle and polymer–particle interaction. Also, the glass‐transition temperature as a function of filler content was obtained and was related to the results obtained for the apparent activation energies of the α relaxation, which were estimated with the Williams, Landel, and Ferry equation. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 883–892, 2003
Self‐assembling metal coatings from phosphated and siloxane‐modified polyurethane dispersions: An analysis of the coating–air interface
Authors: Mequanint K. , Sanderson R. 
Published: February 2003

AbstractPolyurethane dispersion coatings containing phosphate and siloxane chains were evaluated for their self‐assembling properties for a single‐coating system. Dynamic contact angles (DCAs) and X‐ray photoelectron spectroscopy (XPS) were used to study the coating–air interface. The siloxane chains were the predominant species on the surfaces of the coatings. The wetting properties of the coating–air interface were reversed when the coated panels were immersed in an ionic solution, and the decrease in hydrophobicity was linear with time. Results from XPS and DCA analyses were similar. The self‐assembling properties of the coatings could be useful in the development of hydrophobic coatings from hydrophilic polymers. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 893–899, 2003
Rheological cure characterization of phosphazene–triazine polymers
Authors: Reghunadhan Nair C.P. , Ninan K.N. 
Published: February 2003

AbstractCyclomatrix phosphazene–triazine network polymers were synthesized by co‐curing a blend of tris(2‐allylphenoxy), triphenoxy cyclotriphosphazene (TAP), and tris(2‐allylphenoxy) s‐triazine (TAT) with bis(4‐maleimido phenyl) methane (BMM). The co‐curing of the three‐component resin was investigated by dynamic mechanical analysis using rheometry. The cure kinetics of the Diels–Alder step was studied by examining the evolution of the rheological parameters, such as storage modulus (G′), loss modulus (G″), and complex viscosity (η*), for resins of varying compositions at different temperatures. The curing conformed to an overall second‐order phenomenological equation, taking into account a self‐acceleration effect. The kinetic parameters were evaluated by multiple‐regression analysis. The absence of a definite trend in the cure process with blend composition ratio was attributed to the occurrence of a multitude of competitive reactions whose relative rates depend on the reactant ratio and the concentration of the products formed from the initial phase of reaction. The cure was accelerated by temperature for a given composition, whereas the self‐acceleration became less prominent at higher temperature. Gelation was accelerated by temperature. The gel conversion decreased with increase in maleimide concentration and, for a given composition, it was independent of the cure temperature. The activation energy for the initial reaction and the crosslinking process were estimated for a composition with a maleimide‐to‐allyl ratio of 2 : 1. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 908–914, 2003
Cyclization reaction in poly(acrylonitrile/itaconic acid) copolymer: An isothermal differential scanning calorimetry kinetic study
Authors: Devasia Renjith , Nair C. P. Reghunadhan , Sivadasan P. , Katherine B. K. , Ninan K. N. 
Published: February 2003

AbstractThe kinetics of the cyclization reaction in the poly(acrylonitrile/itaconic acid) (PAN) copolymer in the temperature range 175–200°C was studied by isothermal differential scanning calorimetry (DSC). The reaction conforms to an nth‐order autocatalytic model, with an overall order of 2. The kinetic parameters were derived by multiple regression analysis. The activation energy is 110.3 kJ/mol for the acid‐catalyzed reaction and 153.2 kJ/mol for the autocatalytic part. The autocatalysis indicates the catalysis of the nitrile group cyclization by the initially formed pyrimidine groups. The kinetic parameters were used to predict the reaction profile at a given temperature. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 915–920, 2003
Compatibilization efficacy of poly(isoprene–butyl acrylate) block copolymers in natural/acrylic rubber blends
Authors: Wootthikanokkhan J. , Tongrubbai B. 
Published: February 2003

AbstractPoly(isoprene–butyl acrylate) block copolymers with a variety of molecular weights and compositions were prepared via a controlled free‐radical polymerization with an iniferter. Subsequently, the block copolymers were used as compatibilizers in natural/acrylic rubber blends. Scanning electron micrographs revealed a cocontinuous morphology in the case of the normal blends with a low natural rubber content (20 wt %), whereas the blends that contained more natural rubber showed a dispersed‐particle morphology. When the rubbers were blended with 5 wt % block copolymer, the particle size decreased, and the tensile strength of the resulted blends increased, regardless of the block copolymer characteristics. For the blend that exhibited a cocontinuous morphology, the most effective compatibilizer was the block copolymer with an average molecular weight of 22,000 g/mol, containing mainly (87%) polyisoprene block. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 921–927, 2003
Modification of polyethylene–octene elastomer by silica through a sol–gel process
Authors: Wu Chin‐San , Liao Hsin‐Tzu 
Published: February 2003

AbstractIn this study, tetraethoxysilane (TEOS) and a metallocene polyethylene–octene elastomer (POE) were chosen as the ceramic precursor and the continuous phase, respectively, for the preparation of new hybrids by an in situ sol–gel process. To obtain a better hybrid, a maleic anhydride‐grafted polyethylene–octene elastomer (POE‐g‐MAH), used as the continuous phase, was also investigated. Characterizations of POE‐g‐MAH/SiO2 and POE/SiO2 hybrids were performed by Fourier transform infrared (FTIR) and 29Si solid‐state nuclear magnetic resonance (NMR) spectrometers, a differential scanning calorimeter (DSC), a thermogravimetry analyzer, and an Instron mechanical tester. The results showed that the POE‐g‐MAH/SiO2 hybrid could improve the properties of the POE/SiO2 hybrid because the interfacial force between the polymer matrix and the silica network was changed from hydrogen bonds into covalent SiOC bonds through dehydration of hydroxy groups in POE‐g‐MAH with residual silanol groups in the silica network. The existence of covalent SiOC bonds was proved by FTIR spectra. For the POE/SiO2 and POE‐g‐MAH/SiO2 hybrids, maximum values of the tensile strength and the glass transition temperature were found at 9 wt % SiO2 since a limited content of silica might be linked with the polymer chains through the covalent bond. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 966–972, 2003
Theoretical energy consideration of the gas‐phase polymerization of sodium acrylate
Authors: Sanderson Ronald D. , Sadiku E. Rotimi 
Published: February 2003

AbstractThe kinetics of the spray polymerization of sodium acrylate were investigated. The technique in which the heat of polymerization was used for solvent removal showed better energy efficiency than the solution or emulsion polymerization methods for preparing sodium polyacrylate. The monomer solution was injected into the nozzle of the spray machine via a venturi effect to siphon up the solution. Two siphon tubes feeding through two control valves into a mixing chamber before the spray operation resulted in separate feeds of a sodium hydroxide solution and a mixture of acrylic acid, water, and a catalyst. These two feeds generated the heat of neutralization of sodium acrylate. This heat raised the temperature of the monomer solution to the reaction temperature, thereby initiating the exothermic polymerization reaction. Theoretical calculations of these energy sources were compared with the energy required to give a dry product. The results revealed that the energy cost for spray polymerization was 4783.5 kJ kg−1, whereas the energy cost was 7830.4 kJ kg−1 for the conventional system. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 928–935, 2003
Initiation of surface graft polymerization by ceric ions on polymer microspheres
Authors: Wang Ping‐Hua 
Published: February 2003

AbstractThe surface graft polymerization of acrylamide on poly(styrene‐co‐acrylonitrile) copolymer microspheres by the initiation of ceric ions was studied. The grafting was verified by IR spectra and X‐ray photoelectron spectroscopy measurements. The resultant microspheres with surface‐grafted polymer chains were employed in the preparation of polymer‐microsphere‐supported palladium composite particles. The composite particles were then studied by transmission electron microscopy and X‐ray diffraction. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 936–940, 2003
Miscibility and phase structure of binary blends of polylactide and poly(vinylpyrrolidone)
Authors: Zhang Guobao , Zhang Jianming , Zhou Xiaoshu , Shen Deyan 
Published: February 2003

AbstractThe miscibility, crystallization behavior, and component interactions of two binary blends, poly(L‐lactide) (L‐PLA)/poly(vinylpyrrolidone) (PVP) and poly(D,L‐lactide) (DL‐PLA)/PVP, were studied with differential scanning calorimetry and Fourier transform infrared (FTIR) spectroscopy. The composition‐dependent changes of the glass‐transition temperature (Tg) and degree of crystallinity (Xc) of the L‐PLA phase indicated that L‐PLA and PVP were immiscible over the composition range investigated. However, the sharp decrease of Xc with increasing PVP content in the second heating run demonstrated that the cold crystallization process of L‐PLA was remarkably restricted by PVP. In DL‐PLA/PVP blends, the existence of two series of isolated Tg's indicated that DL‐PLA and PVP were phase‐separated, but evidence showed that there was some degree of interaction at the interface of the two phase, especially for the blends with low DL‐PLA contents. FTIR measurements showed that there was no appreciable change in the spectra of L‐PLA/PVP with respect to the coaddition of each component spectrum, implying the immiscibility of the two polymers. In contrast to L‐PLA, the intermolecular interaction between DL‐PLA and PVP was detected by FTIR; this was evidenced by the observation of a high‐frequency shift of the CO stretching vibration band of PVP with increasing DL‐PLA content, which suggested some degree of miscibility. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 973–979, 2003
Molecular mobility in starchy materials studied by electron spin resonance
Authors: Riquet Anne‐Marie , Feigenbaum Alexandra , Colonna Paul , Lourdin Denis 
Published: February 2003

AbstractPhase transitions in hydrated starch–sorbitol system were investigated both by molecular (electron spin resonance, ESR) and macroscopic (differential scanning calorimetry, DSC) methods. In rapid‐tumbling region, one did not observe the same phenomena by DSC and by ESR. The transitions observed by ESR, which seemed to reflect more the interactions probe–matrix than plasticization, probably corresponded to the interactions probe–sorbitol. For system concentrated in plasticizer, it was conceivable to admit that a demixion of sorbitol occurred. In slow‐tumbling region, a correspondence in temperature mobility changes measured by mechanical spectroscopy and ESR was observed. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 990–997, 2003
Influence of fillers on the mechanical response of an amorphous liquid‐crystalline polymer
Authors: Guerrica‐Echevarría G. , Eguiazábal J. I. , Nazábal J. 
Published: February 2003

AbstractA semirigid and amorphous commercial liquid‐crystalline copolyester (Rodrun) was filled with mica and calcium carbonate (up to 25 wt %) by direct injection molding. The fillers led to decreases in the processability, as observed by torque increases, but maintained the thermal resistance of Rodrun. The effects of the two fillers on the modulus of elasticity, ductility, and tensile strength were the same or very similar. The decrease in the tensile strength (20% for a 10% filler content) was compensated by a generally slight increase in the modulus of elasticity, whatever the filler content was. This balance of properties found in these new liquid‐crystalline‐polymer‐based materials and the important savings that the fillers bring may spread the applications of these materials' matrices. © 2003 Wley Periodicals, Inc. J Appl Polym Sci 88: 998–1003, 2003
High‐resolution carbon nuclear magnetic resonance study of styrene/α‐methylstyrene/acrylonitrile terpolymers
Authors: Nogueira Regina F. , Tavares Maria Inês B. 
Published: February 2003

AbstractTerpolymers formed from styrene, α‐methylstyrene (AMS), and acrylonitrile (AN) were prepared in different proportions. According to the reaction conditions, the terpolymers presented random sequence distributions. AMS, because of steric hindrance, presented a high degree of instability, which promoted depolymerization. AN promoted a long insertion of AMS monomers, which caused an acceleration of the propagation reaction. This also caused a depolymerization process. With 13C‐NMR solution analysis, it was possible to detect the depolymerization process. With solid‐state NMR results, it was demonstrated that AMS constituted the highest mobility domain. Finally, the values determined for the proton spin–lattice relaxation time in the rotating frame confirmed that the prepared terpolymers were random, but a homogeneous monomer distribution sequence was also observed from this parameter. © 2003 Wley Periodicals, Inc. J Appl Polym Sci 88: 1004–1009, 2003
Modeling and analysis of a gas sweeping process for polycarbonate polymerization
Authors: Kim Dae‐Hyung , Ha Kyoung‐Su , Rhee Hyun‐Ku , Ho Song Kwang 
Published: February 2003

AbstractThis article deals with (1) the development of a mathematical model for the finishing polycarbonate polymerization process with a horizontal, rotating disk‐type reactor with countercurrent gas sweeping and (2) the performance analysis of the reactor system with the model. We propose a model describing a reactor system consisting of two phases in which the byproduct (phenol) is removed from the polymer melt phase to the countercurrently flowing vapor phase to facilitate the forward reaction and, therefore, produce a high molecular weight polymer compatible with the products of commercial grades. The vapor phase is represented by the tanks‐in‐series model, whereas the polymer melt phase is regarded as a plug flow reactor. The major concerns here are the influences of the reactor operating conditions, including the catalyst concentration, reaction temperature, mass‐transfer rate, melt‐phase residence time, and vapor‐phase velocity, on the polymer molecular weight, the melt‐phase concentrations of various components, and the molar fraction of phenol in the vapor phase. To corroborate the validity of the proposed model and investigate the complex phenomena of the process, we have conducted a series of simulation studies with various operating policies, and we compare the performance of the process with the performances of the cocurrent process and the vacuum process. According to the results of this study, this new type of reactor system shows satisfactory performance and is sometimes even better than the conventional high‐ vacuum process. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 1010–1021, 2003
Novel refreshableN‐halamine polymeric biocides: Grafting hydantoin‐containing monomers onto high performance fibers by a continuous process
Authors: Sun Yuyu , Sun Gang 
Published: February 2003

AbstractIn this study, a continuous “pad‐dry‐cure” process was developed for the first time to graft a cycloamine monomer, 3‐allyl‐5,5‐dimethylhydantoin (ADMH), onto several high performance fibers, including Nomex, Kermel, and a PBI/Kevlar blend. The influence of reaction conditions on the grafting copolymerizaiton was studied. It was found that in the presence of a difunctional monomer, poly(ethylene glycol)–diacrylate (PEG–DIA), ADMH could be readily grafted onto these fibers. After exposure to chlorine, the hydantoin structures in the grafted samples could be transformed intoN‐halamines, which provided powerful, durable, and regenerable antibacterial activities against both gram‐negative and gram‐positive bacteria. The influence of hydrophobic/rigid properties of the fabrics on grafting reactions as well as on their antibacterial activities was discussed, and the importance of full contact was emphasized. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 1032–1039, 2003
Mechanical properties of epoxy‐based hybrid composites containing glass beads and α,ω‐oligo(butylmethacrylate)diol
Authors: Schröder N. , Könczöl L. , Döll W. , Mülhaupt R. 
Published: February 2003

AbstractA novel phase‐separating liquid rubber based on oligo(alkylmethacrylate) in combination with microglass beads was used to toughen an anhydride‐cured epoxy resin. The resulting hybrid composites, containing 5 or 10 wt % of oligomeric liquid rubber and between 10 and 60 wt % glass beads as well as composites containing corresponding amounts of glass beads but no liquid rubber, were characterized mechanically. The experimental data show that modification with glass beads results in increased stiffness and toughness compared to the neat resin but reduces tensile strength. Compared to the glass bead–filled composites, additional modification with methacrylic rubber leads to a further increase in toughness and also to an increase in strength but does not alter stiffness and glass‐transition temperature. This synergistic behavior is explained by the fact that the rubber separates preferably on the surface of the glass bead, forming a core–shell morphology during curing. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 1040–1048, 2003
Synthesis and kinetic behavior of stereotriblock polybutadiene using dilithium as initiator
Authors: Wang Yurong , Li Guanghui , Leng Ying , Yang Xiao , Gu Mingchu 
Published: February 2003

AbstractAnionic polymerization of butadiene was conducted in cyclohexane using 1,1,4,4‐tetraphenyl‐1,4‐dilithium butane (TPB–DiLi) as initiator and dipiperidinoethane (DPE) as modifier. The polymer design effects of DPE/TPB–DiLi (simplified as DPE/Li) and polymerization temperature on the 1,2 content of polybutadiene (PB) were examined and 1,2‐polybutadiene (1,2‐PB) with a nearly 100% 1,2 content was obtained. 1,2–1,4–1,2‐Stereotriblock polybutadiene (STPB) can be synthesized easily by means of one feed reaction. DSC and DMA analyses showed that STPB with the designed molecular structure (molecular weight, block ratio, and 1,2 content in 1,2 blocks) has two Tg's and two loss moduli and exhibits microphase separation. Studies on reaction kinetics established the polymerization kinetics equation of 1,4‐PB as −d[M]/dt = 0.356[C]0.5[M], indicating the first‐order relationship between polymerization rate and monomer concentration. At 50°C, the addition of the strong polar modifier DPE into the system increased the reaction rate. The apparent propagating activating energies before and after DPE addition were also determined in this study. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 1049–1054, 2003
Structure and thermal degradation of poly(N‐phenyl acrylamide) and poly(N‐phenyl methacrylamide)
Authors: Li Xin‐Gui , Huang Mei‐Rong , Zhu Zhi‐Liang , Jin Yi , Wang Xue‐Song 
Published: February 2003

AbstractPoly(N‐phenyl acrylamide) (PPA) and poly(N‐phenyl methacrylamide) (PPMA) were prepared by using N‐phenyl acrylamide and N‐phenyl methacrylamide as monomer, respectively, in tetrahydrofuran using azobisisobutyronitrile as initiator. FT‐IR, 1H‐NMR, and GPC were used to characterize their molecular structure. The PPA obtained exhibited higher molecular weight and wider molecular weight distribution than that of PPMA. Their thermal degradation and kinetics were systematically investigated in two atmospheres of nitrogen and air from room temperature to 800°C by thermogravimetric analysis at 10°C/min. Based on the thermal decomposition reactions in nitrogen and air, it is shown that a three‐step degradation process in nitrogen and a four‐step degradation process for two polymers were observed in this investigation. The initial thermal degradation temperature was lower than 190°C. Under two atmospheres, PPA exhibits higher degradation temperature, higher temperature at the maximum weight‐loss rate, faster maximum weight‐loss rates, and larger weight loss for the first‐stage decomposition, as well as higher char yield at 500°C than those of PPMA. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 1065–1071, 2003