bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effect of high polymerization temperature on the microstructure of isotactic polypropylene prepared using heterogeneous ticl4/mgcl2 catalysts
Authors: Zhong Chifeng , Gao Mingzhi , Mao Bingquan 
Published: October 2003

AbstractThe effects of alkylaluminum and polymerization temperature on propylene polymerization without an external donor in the use of a TiCl4–MgCl2–diether(BMMF) catalyst were investigated. The results indicated that with increasing polymerization temperature the concentrations of [mmmm] of heptane‐insoluble poly(propylene) (PP) fraction increased. Crystallization analysis fractionation (CRYSTAF) results showed the fractions of different crystallization temperatures were changed according to various polymerization temperatures. The activity with Et3Al as cocatalyst at 100°C was much lower than that at 70°C. However, the activity with i‐Bu3Al at 100°C was as high as that at 70°C. The fraction of high‐crystallization temperature of PPs obtained with i‐Bu3Al increased with increasing polymerization temperature, which was opposite to that with Et3Al, thus implying that the copolymerization of propylene with the monomer arising from Et3Al led to the lower crystallization ability of PPs obtained with Et3Al. The terminal groups of PP suggested that the chain‐transfer reaction by β‐H abstraction was the main chain‐transfer reaction at 120°C. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 3980–3986, 2003
Peroxydisulfate initiated graft copolymerization of aniline onto poly(propylene) fiber—A kinetic approach
Authors: Anbarasan R. , Jayaseharan J. , Sudha M. , Gopalan A. 
Published: October 2003

AbstractA novel method for the preparation of electrically conducting fibers through chemical grafting of electrically conducting polymer onto poly(propylene) (PP) fiber is described. The graft copolymerization of aniline (ANI) was performed in aqueous acidic medium by using a chemical oxidant such as peroxydisulfate (PDS). Grafting occurred with simultaneous homopolymer formation. The content of polyaniline in the backbone fiber was found to vary by varying [monomer], [initiator], and amount of PP fiber. Various graft parameters such as rate of grafting (Rg), % grafting, and % grafting efficiency were evaluated. The rate of homopolymerization (Rh) was also determined. Both Rh and Rg showed first‐order dependency on [ANI], [PDS], and amount of PP fiber variation. The chemical grafting was confirmed by use of cyclic voltammetry and conductivity measurements. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 3827–3834, 2003
Synthesis and characterization of new hydrogels on the basis of water‐soluble maleic anhydride copolymers with γ‐aminopropyltriethoxysilane
Authors: Kaplan Can Hatıce , Rzaev Zakır M. O. , Güner Alı 
Published: October 2003

AbstractThis work describes the synthesis and macromolecular reactions of maleic anhydride (MA)–acrylic acid (AA) binary reactive copolymers with γ‐aminopropyltriethoxysilane (APTS) as a polyfunctional crosslinker. Copolymers with a given composition of MA–AA (47.17–52.83 wt %) were synthesized by radical binary copolymerization with benzoyl peroxide as an initiator in p‐dioxane at 70°C in nitrogen atmosphere and initial monomer ratio of 1 : 1. It is shown that the network structure is formed in MA–AA/APTS in water by intermolecular reaction between the anhydride unit and the amine group, as well as between the etoxysilyl fragment and free carboxyl groups of the acrylic acid and maleic anhydride unit. Swelling parameters such as beginning time of hydrogel formation, initial rate of swelling, swelling rate constant, equilibrium swelling, and equilibrium water content were determined for copolymer/APTS/water systems with various copolymer/crosslinker ratios. Formation of a hyperbranched network structure through the fragmentation of side‐chain reactive groups in the studied systems was confirmed by FTIR, TGA, and DSC methods. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 4009–4015, 2003
Effects of temperature and stress level on creep and tensile property of polypropylene sutures
Authors: Deng Meng , Zhou Jack 
Published: October 2003

AbstractAn investigation was conducted on creep behaviors of polypropylene sutures under different temperatures and stress levels in a temperature‐controlled water bath. The study showed that temperature and stress level significantly affected the creep behaviors of the sutures. High temperature and stress level resulted in large creep and permanent deformation to the sutures. The creep data could be well described by an empirical formula. For most of the test conditions, the creep tests caused limited permanent deformation in sutures. Dependency of the permanent deformation on temperature may be illustrated by an Arrhenius‐type equation. The tensile properties of the sutures were not adversely affected by a short‐term creep test, indicating good mechanical performance for the polypropylene sutures. For the creep experiment of less than 3 h, the creep rupture of the sutures was observed at a stress level of 220 MPa and temperatures ≥ 37°C. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 3882–3888, 2003
Temperature effects of electrical resistivity of conductive silicone rubber filled with carbon blacks
Authors: Zhang Jie , Feng Shengyu 
Published: October 2003

AbstractThe temperature effects of electrical resistivity of conductive silicone rubber filled with widely varying concentrations of carbon blacks (CBs: GPF 660 carbon black, HAF N‐330 carbon black, VXC‐72 conductive carbon black, and BP2000 superconductive carbon black) were studied from 30 to 200°C. Both low positive temperature coefficient (L‐PTC) and negative temperature coefficient (NTC) phenomena were observed, whose intensity and temperature range depend on the type and the concentration of CBs. A stronger temperature dependency of resistivity was observed when the CB concentration was in the percolation region. Unlike crystalline polymers/CBs composites, the high positive temperature coefficient (H‐PTC) phenomenon was not observed in CB‐filled silicone rubber when the CB concentration was near the percolation threshold. Generally, pronounced the NTC phenomenon appears in composites with small particles of CBs at concentrations near the percolation threshold, whereas a pronounced PTC phenomenon appears in composites with large CB particles of at concentrations exceeding the percolation region. If both PTC and NTC phenomena were in the same sample of conductive silicone rubber, the PTC phenomenon always appeared at relatively low temperatures and NTC at relatively high temperatures. The results were discussed. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 3889–3895, 2003
Influence of additional thermal stabilizers on the reprocessing of postconsumer poly(vinyl chloride) bottles
Authors: Ulutan Sevgi 
Published: October 2003

AbstractThe addition of heat stabilizers is essential for preventing the degradation of poly(vinyl chloride) (PVC) during its processing. The heat stabilizers consumed in the first run have to be made up before the reprocessing of recycled PVC. In this study, solvent‐cast films, which were prepared from granulated postconsumer PVC bottles mixed with plasticizers and thermal stabilizers, were used. The films were subjected to various heat treatments. No considerable structural change upon heat treatments at 140–160°C was found in IR and differential scanning calorimetry analyses. Polyene formation observed through ultraviolet analysis was not severe, indicating that the added stabilizers worked well in preventing degradation. The weight loss during the heat treatments was attributed partly to the decomposition of PVC and the evaporation of volatile components and mainly to the removal of the solvent upon heating. Although this study was conducted with water bottles that were to be recycled, it may be equally well applied to other similarly formulated PVC‐based materials, such as packaging films. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 3994–3999, 2003
Use of rice bran oil and epoxidized rice bran oil in carbon black–filled natural rubber–polychloroprene blends
Authors: Kuriakose A. P. , Varghese Mohan 
Published: October 2003

AbstractIn the present study we report the results obtained on the use of rice bran oil (RBO), a naturally occurring nontoxic oil, and its epoxidized variety (epoxidized RBO, or ERBO) in the compounding and vulcanization of different natural rubber–chloroprene rubber (NR–CR) blends. The processability, cure characteristics, and physical properties of the blends prepared with these oils were compared with those of control mixes prepared with aromatic oil. The optimum cure time and scorch time values of the different blends prepared with these oils were found to be lower than those of the respective control blends prepared with aromatic oil. Evaluation of physical properties of the different experimental blends showed that replacement of aromatic oil with these oils did not adversely affect their physical properties. Because RBO contains a good amount of free fatty acids it was tried as a coactivator in addition to its role as a processing aid. The level of these oils required for the blend preparation was optimized in a Brabender plasticorder. Physical properties such as tensile strength, elongation at break, tear strength, swelling index, and abrasion loss, for example, were evaluated for both experimental and control mixes. Comparison of cure characteristics and physical properties of the blends prepared with aromatic oil and with these oils showed that these oils could be used in place of aromatic oil in the above blends. It is also to be noted that aromatic oil is of petroleum origin and is reported to be carcinogenic. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 4084–4092, 2003
Postgrafting of congo red dye onto hyperbranched mesoporous silica with terminal amino groups
Authors: Seçkin Turgay , Gültek Ahmet 
Published: October 2003

AbstractCongo red dye has been postgrafted onto mesoporous silica that was prepared by the controlled hydrolysis of tetraethyl orthosilicate in the presence of organic agents. Surface grafting of mesoporous silica having amino groups as initiator sites was prepared from γ‐aminopropyltrimethoxysilane by sol‐gel process. The postgrafting reaction of Congo red onto silica with terminal amino groups was achieved by a repeated step of the addition of methyl acrylate to amine groups followed by the amidation of the resulting ester moieties with ethylene diamine. Postgrafting efficiency of all materials has been outlined. Because postgrafting efficiency values have been found to be smaller than theoretical values, it is concluded that the resulting product was more likely to be a hyperbranched polymer rather than a true dendrimer at higher generations. The postgrafted structures with amino‐terminal groups provide an attractive site for binding Congo red dye that not only persists in its characteristic properties, but also has exceptional hybrid properties possessed by mesoporous silica. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 3905–3911, 2003
Effect of membrane morphology in pervaporative separation of isopropyl alcohol–aromatic mixtures— a thermodynamic approach to membrane selection
Authors: Mandal Sangita , Pangarkar Vishwas G. 
Published: October 2003

AbstractIsopropyl alcohol (IPA)–benzene and IPA–toluene, which forms azeotropic mixtures, are commonly encountered in pharmaceutical industries. The present study deals with the use of pervaporation to separate these mixtures. For this purpose, several polymeric hydrophilic membranes with variation in solubility parameters such as regenerated cellulose or cellophane, poly(vinyl alcohol) (PVA), cellulose acetate (CA), cellulose diacetate (CDA), and cellulose triacetate (CTA) were studied. Some of these membranes gave a gradual shift of azeotropic point according to the variation of solubility parameter and interaction parameter values between solute and polymer matrix. Regenerated cellulose film gave the best pervaporation performance in terms of IPA selectivity and durability. PVA showed high selectivity with reasonable flux. Poly(dimethylsiloxane), which is hydrophobic, was also studied as an aromatic selective membrane. The experiments were carried out over the entire range of 0–100% at 30°C. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 3912–3921, 2003
Study of the properties and reliability of EMC packaging material
Authors: Chiu Hsien‐Tang , Chung Jung‐Sheng 
Published: October 2003

AbstractThermoplastic nylon powder with a low melting point was added to Biphenyl Epoxy to serve as a forming stress release agent that is intended to reduce the stress resulting from Epoxy Molding Compound (EMC). The purpose of this study was to explore the physical impact and effect on the formed object after adding nylon powder to Biphenyl Epoxy. Mechanical properties were explored through the Izod impact test and the three‐point bending test. Thermal Mechanical Analysis and Dynamic Mechanical Analysis were conducted to probe the coefficient of thermal expansion (CTE) and the glass transition temperature (Tg). The rate of water absorption was measured via a test of the pressure cook test (PCT), and insulation resistance was assessed through the insulating destruction experiment. The results indicate that adding nylon powder increases the fracture energy of the epoxy‐formed material; however, mechanical properties decreased slightly. TMA showed that the CTE (α1) decreased when nylon was added, and DMA revealed that heat resistance decreased slightly. The water absorption rate test and the PCT test showed that the rate of water absorption increased to a small extent, whereas the breakdown voltage (BDV) decreased slightly. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 3928–3933, 2003
Relationship among phase morphology, oil resistance, and thermal aging properties in CPE/NR blends: effect of blending conditions
Authors: Sirisinha Chakrit , Saeoui Pongdhorn , Guaysomboon Jantagarn 
Published: October 2003

AbstractThe CPE/NR blends with blend ratio of 50/50% by weight were prepared with various blending conditions. The resistance to oil and thermal aging of the blends was investigated and correlated with phase morphology. The NR dispersed phase size in blends was found to decrease with increasing rotor speed up to 45 rpm and subsequently level off at higher rotor speeds. With increasing mixing time at a given rotor speed, NR dispersed phase size reached a minimum and increased again with a further increase in mixing time, caused by domain breakup and phase coalescence, respectively. In addition, the results revealed a strong relationship between NR phase size and resistances to oil as well as thermal aging, that is, the smaller the dispersed phase size, the higher the oil resistance and the thermal aging properties. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 4038–4046, 2003
Synthesis and characterization of poly(urethane‐benzoxazine)/clay hybrid nanocomposites
Authors: Takeichi Tsutomu , Guo Yong 
Published: October 2003

AbstractPoly(urethane‐benzoxazine)/clay hybrid nanocomposites (PU/Pa–OMMTs) were prepared from an in situ copolymerization of a polyurethane (PU) prepolymer and a monofunctional benzoxazine monomer, 3‐phenyl‐3,4‐dihydro‐2H‐1,3‐benzoxazine (Pa), in the presence of an organophilic montmorillonite (OMMT), by solvent method using DMAc. OMMT was made from cation‐exchange of Na‐montmorillonite (MMT) with dodecyl ammonium chloride. The formation of the exfoliated nanocomposite structures of PU/Pa‐OMMT was confirmed by XRD from the disappearance of the peak due to the basal diffraction of the layer‐structured clay found in both MMT and OMMT. DSC showed that, in the presence of OMMT, the curing temperature of PU/Pa lowered by ca. 60°C for the onset and ca. 20°C for the maximum. After curing at 190°C for 1 h, the exothermic peak on DSC disappeared. All the obtained films of PU/Pa–OMMT were deep yellow and transparent. As the content of OMMT increased, both the tensile modulus and strength of PU/Pa–OMMT films increased, while the elongation decreased. The characteristics of the PU/Pa–OMMT films changed from plastics to elastomers depending on OMMT content and PU/Pa ratio. PU/Pa–OMMT films also exhibited excellent resistance to the solvents such as tetrahydrofuran, N,N‐dimethylformamide and N‐methyl‐2‐pyrrolidinone. The thermal stability of PU/Pa were enhanced remarkably even with small amount of OMMT. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 4075–4083, 2003
Low‐temperature carrier dyeing of poly(vinyl chloride) fibers with disperse dyes
Authors: Kim Ik Soo , Cho Han Moon , Koh Joonseok , Kim Jae Pil 
Published: October 2003

AbstractThe effects of various carriers on the color yield of poly(vinyl chloride) (PVC) filaments in a disperse dyeing system were investigated. The dyeability of disperse dyes on PVC fiber was improved using appropriate carriers. The enhancement of dye uptake imparted by carriers coincided with the reduction in glass‐transition temperature, which in turn coincided approximately with the similarity of the inorganic/organic ratio values between PVC fibers and carriers. The results clearly demonstrate that hydrophobic carriers function as diluents of PVC fiber, facilitating dye diffusion by increasing segmental mobility of the fiber. The dyed PVC filaments with disperse dyes showed reasonable levels of build‐up and color fastness properties in the carrier‐assisted dyeing. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 3896–3904, 2003
Supercritical CO2 extraction of phthalate plasticizers from PVC
Authors: Shieh Yeong‐Tarng , Hsiao Tzu‐Ting , Lung Tzu‐I , Yang Huang‐Shung 
Published: October 2003

AbstractThree common phthalates, namely, dioctyl phthalate, diisodecyl phthalate, and trioctyl trimellitate, were used as plasticizers for poly(vinyl chloride) (PVC) processing, and the extraction of these plasticizers were investigated using supercritical CO2 fluids. Factors affecting the extractions of these phthalates were focused. The molecular weight of phthalates was found to dominate the level of extraction of low temperatures, whereas the content of carbonyl groups in the phthalate was a determining factor for the level of extraction of high temperatures. Negligible extraction was observed below the critical pressure of CO2. For 32°C, the level of the extraction is insignificant below density of ca 0.7 g/cm3, above which the level of the extraction increases roughly linearly with increasing density. For temperatures above 32°C, the density of CO2 for apparent extractions decreased with increasing temperatures. The threshold density of CO2 for extractions was found to be independent of the amount of a given phthalate in PVC. Two extraction rates during the extraction could be determined, with a higher rate in the first hour followed by a lower rate later in the extraction for all three phthalates. The effects of the extractions of phthalates on the flexibility of PVC were also investigated as well as the effects of the extrusion conditions, which could lead to various degrees of plasticization of PVC, on the level of extractions. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 4032–4037, 2003
Preoperative treatment of hepatocellular carcinoma with intra-arterial injection of 131I-labelled lipiodol
Authors: Raoul J-L , Messner M , Boucher E , Bretagne J-F , Campion J-P , Boudjema K 
Published: October 2003

Abstract

Background
Recurrence is common after surgery for hepatocellular carcinoma (HCC).

Methods
The efficacy of, and tolerance to, preoperative intra-arterial injection of 131I-labelled lipiodol was examined in 34 patients with HCC, including 29 with cirrhosis. Twenty-five patients had a single hepatic tumour and the mean(s.d.) tumour size was 5·2(3·7) (range 2–15) cm. The patients received between one and three injections of 131I-labelled lipiodol (60 mCi per injection) before surgery. Operations included 14 liver transplants, 13 minor hepatectomies, six major hepatectomies and one exploratory laparotomy.

Results
There was one complication after lipiodol injection due to acute ischaemia of the small bowel. Three of 34 patients died within 28 days, two after transplantation and one after resection. An objective tumour response (decrease in tumour size) was observed in 19 of 34 patients, and a complete histological response in eight of 34. There was an objective tumour response or major histological necrosis of lesions in 25 of 34 patients. The 5-year survival rate was 48·4(8·0) per cent, 69·0 per cent after transplantation and 36·0 per cent in patients who underwent resection.

Conclusion
This preoperative method appeared to be well tolerated, and provided promising results in terms of macroscopic and microscopic tumour responses.
Population-based study of the surgical workload and economic impact of bowel obstruction caused by postoperative adhesions
Authors: Kössi J , Salminen P , Rantala A , Laato M 
Published: October 2003

Abstract

Background
Intestinal obstruction is the most severe consequence of adhesion formation. This study examined the annual surgical workload and costs of intestinal obstruction caused by postoperative intra-abdominal adhesions.

Methods
The study was a retrospective case-note review of patients hospitalized for intestinal obstruction caused by postoperative adhesions in a well defined geographical area. The surgical workload and direct costs of inpatient care were analysed.

Results
There were 138 admissions for postoperative adhesion-related intestinal obstruction during the study with a total of 1118 inpatient days. The median hospital stay was 4 (range 1–58) days among patients who had non-operative treatment and 11 (range 2–34) days for those who had surgery. Surgery was necessary in 40 patients (29·0 per cent). The mean operating time (time from skin incision to last stitch) and the mean time spent in the operating theatre were 79 and 141 min respectively. The cumulative operating time for the surgical group was 52 h 20 min and the cumulative theatre time was 93 h 44 min. The annual direct hospital cost for postoperative adhesional intestinal obstruction was £181 653 in the district studied and the estimated cost for the whole of Finland was £2 077 796.

Conclusion
This population-based study indicates that the workload and costs associated with bowel obstruction caused by postoperative adhesions are substantial.
Use of a continent colonic conduit for treatment of refractory evacuatory disorder following construction of an electrically stimulated gracilis neoanal sphincter
Authors: Saunders J R , Eccersley A J P , Williams N S 
Published: October 2003

Abstract

Background
This study reports the outcome from the addition of a continent colonic conduit (CCC) to an electrically stimulated gracilis neoanal sphincter in patients with severe evacuatory disorder following formation of a neosphincter for end-stage faecal incontinence.

Methods
One hundred and twenty patients had an electrically stimulated gracilis neoanal sphincter constructed for end-stage faecal incontinence. Seven patients developed severe evacuatory disorders; construction of a CCC was required in six patients and an antegrade continence enema procedure in one.

Results
Median follow-up of the seven patients was 77 (range 6–96) months. Six patients with evacuatory disorders had a successful outcome, defined as continence to solid and liquid stool as well as correction of the evacuatory disorder. A stoma was formed in one patient. Patients who had previously undergone anorectal reconstructive surgery were more likely to develop an evacuatory disorder following construction of an electrically stimulated gracilis neoanal sphincter than patients operated on for other reasons (χ2 = 28·13, 1 d.f., P &lt; 0·001).

Conclusion
Construction of a CCC is a useful technique for the majority of patients with severe evacuatory disorders following the formation of an electrically stimulated gracilis neoanal sphincter, for whom the only alternative would be an end stoma. A CCC may be incorporated with construction of an electrically stimulated gracilis neoanal sphincter in patients at significant risk of postoperative severe evacuatory disorders.