bluuebunny/crossref_metadata_2025 huggingface dataset:
Biodegradation study of a coextruded starch and poly(lactic acid) material in various media
Authors: Gattin Richard , Copinet Alain , Bertrand Céline , Couturier Yves
Published: February 2003

The biodegradation of a coextruded starch/poly(lactic acid) polymeric material was studied in a liquid, in an inert solid, and in composting media. Mineralization of the material's carbon content was followed using the appropriate ASTM standard experimental methods. The final percentage of biodegradation depended on the nature of the medium used. The percentage of mineralization (Cg) was better with the liquid medium (65%) than with either the compost medium (64%) or the inert medium (59%). To understand the workings of the biodegradability of the polymer material, a measurement of the carbon balance seemed essential A repartitioning of the material's carbon between the various degradation products to biomass carbon (Cb), to carbon dioxide carbon (Cg), to dissolved organic carbon (Cs), and to residual insoluble material carbon (Cnd) produced was quantified throughout the experimental runs. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 825–831, 2003
Synthesis of syndiotacticity‐rich high molecular weight poly(vinyl alcohol) by suspension polymerization of vinyl pivalate and saponification
Authors: Lyoo Won Seok , Park Chan Sik , Kim Joon Ho , Ghim Han Do , Lee Ji Youl , Lee Jinwon , Lee Chul Joo
Published: February 2003

Vinyl pivalate (VPi) was suspension‐polymerized to synthesize high molecular weight (HMW) poly(vinyl pivalate) (PVPi) with a high conversion above 95% for a precursor of syndiotacticity‐rich HMW poly(vinyl alcohol) (PVA). Also, the effects of the polymerization conditions on the conversion, molecular weight, and degree of branching (DB) of PVPi and PVA prepared by the saponification of PVPi were investigated. Bulk polymerization was slightly superior to suspension polymerization in increasing the molecular weight of PVA. On the other hand, the latter was absolutely superior to the former in increasing the conversion of the polymer, indicating that the suspension polymerization rate of VPi was faster than that of the bulk one. These effects could be explained by a kinetic order of a 2,2′‐azobis(2,4‐dimethylvaleronitrile) concentration calculated by the initial rate method. Suspension polymerization of VPi at 55°C by controlling various polymerization factors proved to be successful in preparing PVA of HMW [number‐average degree of polymerization (Pn): 8200–10,500], high syndiotactic diad content (58%), and very high yield (ultimate conversion of VPi into PVPi: 94–98%). In the case of the bulk polymerization of VPi at the same conditions, the maximum Pn and conversion of 10,700–11,800 and 32–43% were obtained, respectively. The DB was lower and the Pn was higher with PVA prepared from PVPi polymerized at lower initiator concentrations. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 832–839, 2003
Study on the structure of nylon 6 films iodinated before forming. I. Comparison with the film iodinated after forming
Authors: Kang Young Ah , Lee Yang Hun
Published: February 2003

To examine the possibility of applying the iodination of nylon 6 to forming, a new type of nylon 6–iodine complex films iodinated before forming (IBF film) and the old type of films iodinated after forming (IAF film) were prepared and their structures were investigated and compared with each other. The IBF films from iodinated nylon 6 powders could be obtained by a melt press at 185°C, which is much lower than the melt‐press temperature of pure nylon 6 (250°C). It was ascertained that the structure of IAF films is similar to that reported by Lee et al. but the structure of IBF films is very different. The distinctive features of the IBF films compared with the IAF films are as follows: The IBF films have no excess iodine molecules (I2) to form a complex with nylon 6 chains because those molecules in the iodinated powders have been evaporated through the melt press. The IBF films have a practically amorphous structure but only a few crystalline portions with a relaxed state which may have been created with iodide‐ion‐free segments of nylon 6 molecules through the procedure of film forming. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 1138–1144, 2003
Bottom design of carbonated soft drink poly(ethylene terephthalate) bottle to prevent solvent cracking
Authors: Lyu Min‐Young , Pae Youlee
Published: February 2003

The use of a petaloid shape for the bottom design for carbonated PET bottles is widespread. Through this study, the causes of bottom cracking were investigated and a novel petaloid bottom was designed. The variations of the physical properties of PET according to the stretch ratio were examined and the stretch ratios in the blown bottle were analyzed. Cracking phenomena of the bottom were observed by a solvent‐cracking test. The effective stress and the maximum principal stress in a carbonated bottle were analyzed by computer simulation. It was concluded that the bottom crack occurs because of not only the insufficient strength of material due to the insufficient stretch of PET but also to the coarse design of the petaloid shape. The highest maximum principal stress occurred at the valley in the petaloid bottom of the bottle and this strongly affected the cracking in the bottom. The petaloid shape was redesigned to minimize the maximum principal stress, and this resulted in increasing the crack resistance. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 1145–1152, 2003
Improved methods for evaluating the molar mass distributions of cellulose in kraft pulp
Authors: Berggren Rickard , Berthold Fredrik , Sjöholm Elisabeth , Lindström Mikael
Published: February 2003

Multi‐angle laser light scattering (MALLS) was used to characterize birch kraft pulps with respect to their absolute molecular mass distributions (MMDs). The pulps were dissolved in lithium chloride/N,N‐dimethylacetamide and separated by size exclusion chromatography (SEC). The weight‐average and number‐average molecular masses of the cellulose fractions of the pulps obtained from the absolute MALLS measurements were compared with the molar masses obtained by direct‐standard‐calibration relative pullulan standards. Discrepancies between the two detection methods were found, and two ways of correlating the relative pullulan molar masses to the absolute molar masses were examined. In the first method, the correlation was made over a large range of molecular masses. The second method correlated the molecular masses of the standards to the molecular masses of samples by the calculation of fictitious, cellulose‐equivalent molar masses of the standards. With the preferred second method, a more correct MMD of kraft pulp samples could, therefore, be obtained from an SEC system calibrated with narrow standards. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 1170–1179, 2003
Preparation and property of poly(ethylene terephthalate) fibers providing ultraviolet radiation protection
Authors: Teng Cuiqing , Yu Muhuo
Published: February 2003

Interest in protection against solar ultraviolet radiation (UVR) among the general public in the world has been increasing steadily. Poly(ethylene terephthalate) (PET) was blended with UVR‐protection agents and was spun into modified fibers to provide the property of UVR protection. Investigation of this property using a UV spectrophotometer showed that the modified PET fabrics could be resistant to UVR more than 90% in the UV‐B band. The treatment of aqueous alkali on the surface of the fibers to improve the comfortable feel had little influence on the property of UVR protection. Scanning electron microscopy was employed to observe the surface morphology of the fibers. Also, the modified fibers had good heat insulation property and the mechanical properties of the fibers were measured. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 1180–1185, 2003
Process–structure–property relationship in ternary short‐glass‐fiber/elastomer/polypropylene composites
Authors: Tjong S. C. , Xu S. A. , Mai Y. W.
Published: February 2003

Short‐glass‐fiber (SGF)‐reinforced polypropylene (PP) composites toughened with a styrene/ethylene butylene/styrene (SEBS) triblock copolymer were injection molded after extrusion. Furthermore, a maleic anhydride (MA)‐grafted SEBS copolymer (SEBS‐g‐MA) was used as an impact modifier and compatibilizer. The effects of the processing conditions and compatibilizer on the microstructure and tensile and impact performance of the hybrid composites were investigated. In the route 1 fabrication process, SGF, PP, and SEBS were blended in an extruder twice, and this was followed by injection molding. In route 2, or the sequential blending process, the elastomer and PP were mixed thoroughly before the addition of SGF. In other words, either PP and SEBS or PP and SEBS‐g‐MA pellets were premixed in an extruder. The produced pellets were then blended with SGF in the extruder, and this was followed by injection molding. The SGF/SEBS‐g‐MA/PP hybrid fabricated by the route 2 process exhibited the highest modulus, yield stress, tensile stress at break, Izod impact energy, and Charpy drop weight impact strength among the composites investigated. This was due to the formation of a homogeneous SEBS elastomeric interlayer at the SGF and matrix interface of the SGF/SEBS‐g‐MA/PP hybrid. This SEBS rubbery layer enhanced the interfacial bonding between SGF and the matrix of the SGF/SEBS‐g‐MA/PP hybrid. The correlations between the processing, microstructure, and properties of the hybrids were investigated. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 1384–1392, 2003
Stretchable conductive fabric for electrotherapy
Authors: Oh Kyung Wha , Park Hyun Jin , Kim Seong Hun
Published: February 2003

Changes in conductivity with repeated fabric extension were investigated to improve the properties of conductive electrode pad material used for electrotherapy when it is subjected to various movement of human body. Highly stretchable and conductive fabrics were prepared byin situchemical polymerization of polypyrrole on nylon–spandex stretch fabric in aqueous solutions with 0.5 M pyrrole, 1.165 M FeCl3, and 0.165 M benzenesulfonic acid at 5°C for 1 h. Performance of prepared stretchable conductive fabric was evaluated in terms of conductivity changes as a function of tensile strain, repeated extension, and current application time. As the degree of extension increased, the conductivity increased and leveled off when the fabric was subjected to 60% extension. The number of fiber contacts in nylon–spandex fabric with electrode increased as the applied extension increased. However, the conductivity of the composite decreased under excessive extension over 60% since the intrinsic elasticity of fabric became gradually reduced. Generally, the fabric conductivity decreased as the number of extension cycles increased. However, the fabric conductivity was well maintained after repeated extension over 30 cycles at 40% extension. In addition, it was found that the effect of charging during the electrotherapy treatment on a current flow through prepared electrode pad was negligible. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 1225–1229, 2003
Thermal and viscoelastic properties of some commercial starch products
Authors: Contat‐Rodrigo L. , Ribes‐Greus A.
Published: February 2003

Three commercial starch products for polyolefins, marketed under the Mater‐Bi, Cornplast, and Bioefect trademarks, were subjected to an accelerated soil burial test. Their thermal and viscoelastic behaviors were studied by differential scanning calorimetry (DSC) and dynamic mechanical spectroscopy. Degradation in soil leads to more significant changes both in the DSC thermogram and the mechanical relaxation spectrum of Mater‐Bi. The relaxation spectra of Cornplast and Bioefect, two products containing polyethylene, basically coincide with that of pure low density polyethylene. The α‐relaxation zone of these starch products is the most affected by the degradation process. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 1242–1251, 2003
New poly(amide imide imide)s based on tetraimide dicarboxylic acid condensed from 4,4′‐(hexafluoroisopropylidene)diphthalic anhydride, m‐aminobenzoic acid, and 4,4″‐oxydianiline and various aromatic diamines
Authors: Yang Chin‐Ping , Chen Ruei‐Shin , Hsu Mao‐Feng
Published: February 2003

A series of new, organosoluble, and light‐colored poly(amide imide imide)s were synthesized from tetraimide dicarboxylic acid (I) and various aromatic diamines by direct polycondensation with triphenyl phosphite and pyridine as condensing agents. I was prepared by the azeotropic condensation of 4,4′‐(hexafluoroisopropylidene)diphthalic anhydride, m‐aminobenzoic acid, and 4,4′‐oxydianiline at a 2/2/1 molar ratio in N‐methyl‐2‐pyrrolidone (NMP)/toluene. The thin films cast from N,N‐dimethylacetamide (DMAc) had cutoff wavelengths shorter than 400 nm (365–394 nm) and color coordinate b* values between 13.10 and 36.07; these polymers were lighter in color than the analogous poly(amide imide)s and isomeric polymers. All of the polymers were readily soluble in a variety of organic solvents, including NMP, DMAc, N,N‐dimethylformamide, dimethyl sulfoxide, and even less polar dioxane and tetrahydrofuran. The cast films exhibited tensile strengths of 90–104 MPa, elongations at break of 7–22%, and initial moduli of 1.9–2.4 GPa. The glass‐transition temperatures of the polymers were recorded at 274–319°C. They had 10% weight losses at temperatures beyond 520°C and left more than a 50% residue even at 800°C in nitrogen. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 669–679, 2003
Phase dispersion–crosslinking synergism in binary blends of poly(vinyl chloride) with low‐density polyethylene: Entrapping phenomenon in PVC/LDPE/DCP blend
Authors: Ma Guowei , Fang Zhengping , Xu Chengwei
Published: February 2003

The co‐crosslinked products and the entrapping phenomenon that may exist in a poly(vinyl chloride)/low density polyethylene/dicumyl peroxide (PVC/LDPE/DCP) blend were investigated. The results of selective extraction show that unextracted PVC was due to not being co‐crosslinked with LDPE but being entrapped by the networks formed by the LDPE phase. SBR, as a solid‐phase dispersant, can promote the perfection of networks of the LDPE phase when it is added to the PVC/LDPE blends together with DCP, which leads to more PVC unextracted and improvement of the mechanical properties of PVC/LDPE blends. Meanwhile, the improvement of the tensile properties is dependent mainly on the properties of the LDPE networks. Finally, the mechanism of phase dispersion–crosslinking synergism is presented. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 1296–1303, 2003
Effects of NCO/OH molar ratio on miscibility and properties of semiinterpenetrating polymer networks from polyurethane and benzyl konjac glucomannan
Authors: Lu Yongshang , Zhang Lina
Published: February 2003

Semi‐interpenetrating polymer network (semi‐IPN) films with different NCO/OH molar ratios of the urethane prepolymer, coded as UB, were prepared from polyurethane (PU) and benzyl konjac glucomannan (B‐KGM) by a casting method. The effect of the NCO/OH molar ratio of the urethane prepolymer on the miscibility and properties of the UB films was investigated using Fourier transform infrared spectroscopy, differential scanning calorimetry, dynamic mechanical thermal analysis, thermogravimetric analysis, and swelling and tensile tests. The results indicated that, with an increase of the NCO/OH ratio, the crosslink density of the UB films increased, resulting in improved miscibility between PU and B‐KGM and a relatively high light transmittance of the UB films. However, the thermal stability of the UB films decreased with increase of the NCO/OH ratio of the urethane prepolymer, due to the depolymerization of the urethane bonds of the PU networks. When the NCO/OH ratio increased from 2 to 4, the tensile strength of the UB films increased from 15 to 27 MPa, while the breaking elongation decreased from 72 to 16%, resulting from the chemical and physical crosslinks, namely, the enhancement of the covalent bonds and hydrogen‐bonding networks. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 1304–1310, 2003
Isothermal and nonisothermal crystallization kinetics of partially melting nylon 10 12
Authors: Li Yongjin , Zhang Guosheng , Zhu Xinyuan , Yan Deyue
Published: February 2003

Nylon 10 12, a newly industrialized engineering plastic, shows a double‐melting phenomenon during melting. Partial melts were obtained when the sample was heated to the temperature between the two melting peaks. A differential scanning calorimeter was used to monitor the energies of the isothermal and nonisothermal crystallization from the partially melted samples. During isothermal crystallization, relative crystallinity develops with a time dependence described by the Avrami equation, with the exponent n = 1.0. For nonisothermal studies, kinetics treatments based on the Avrami and Ozawa equations are presented to describe the crystallization process. It was found that the two treatments can describe the nonisothermal crystallization from the partially melted samples. The derived Avrami and Ozawa exponents are all about 1.0, which means that the partially melted samples crystallize by one‐dimensional growth, which may cause thickening of the lamellae. We calculated the crystallization activation energies for isothermal and nonisothermal crystallization from the partially melted samples. It was found that the activation energy determined by the Kissinger method was not rational, which may be attributed to the free‐nucleation process for nonisothermal crystallization from partially melted samples. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 1311–1319, 2003
Rheology of poly(n‐butyl methacrylate) and its composites with calcium carbonate
Authors: Chen Jianding , Carrot Christian , Chalamet Yvan , Majeste Jean‐Charles , Taha Mohamed
Published: February 2003

Poly(n‐butyl methacrylate) (PBMA) composites with calcium carbonate (CaCO3) were prepared by in situ radical copolymerization of butyl methacrylate (BMA) and methacrylic acid (MA) with precipitated calcium carbonate. To compare the different rheological behaviors of the monomer mixtures with CaCO3 and the composites, the steady and dynamic viscosities of BMA/MA/CaCO3 and poly(BMA/MA/CaCO3) were measured by means of steady and oscillatory shear flows. The viscosity of the mixture BMA/MA/CaCO3 was found to increase evidently with the increasing of CaCO3%. The influence of MA% on viscosity of BMA/MA/CaCO3 was slight. During the in situ polymerization, the viscosity of the reacting system was measured to be enhanced by a factor of about 104 from the monomer/CaCO3 mixture to composites. The dependency of zero‐shear viscosity on molar mass of PBMA was also investigated. The relation between the zero‐shear viscosity and molar mass is η0 = 10−15 Mw3.5. The evolution of the viscosity with the temperature for both PBMA and its composites was obtained and time–temperature superposition was used to build master curves for the dynamic moduli. The flow activation energies were found to be 115.0, 148.6, and 178.7 kJ/mol for PBMA, composite PBMA/CaCO3 (90/10), and PBMA/MA/CaCO3 (89/1/10), respectively. The viscosity of the composites containing less than 10% CaCO3 was lower than that of pure PBMA with the same molar mass. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 1376–1383, 2003
Analysis and modeling of PVTX diagram of an unsaturated polyester resin, thermoplastic additive, and mineral fillers blend
Authors: Boyard N. , Vayer M. , Sinturel C. , Erre R. , Delaunay D.
Published: February 2003

We studied the dynamic curing of a polymer blend containing an unsaturated polyester prepolymer, styrene, and a saturated polyester as a low‐profile thermoplastic additive during heating from 40 to 160°C with a constant rate (4 or 10 K/min). This work was performed by means of a homemade dilatometer that simultaneously determined conversion degree, volume, pressure, and temperature. The various phenomena inducing volume change were identified and then separated (thermal expansion, shrinkage, and shrinkage compensation). A model based on physical consideration was built that allowed an accurate fit of the experimental results. The influence of the pressure on all this phenomena was summarized and quantified. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 1258–1267, 2003
Fracture behavior of die‐drawn toughened polypropylenes
Authors: Mohanraj J. , Chapleau N. , Ajji A. , Duckett R. A. , Ward I. M.
Published: February 2003

The Leeds die‐drawing process has been used to make oriented sheets of toughened polypropylenes. Die‐drawn oriented sheets were produced by drawing at 110°C to draw ratios of 4, 6, and 10. Comparative measurements have been undertaken of the plane stress fracture toughness at room temperature using the essential work of fracture method for isotropic and oriented polypropylene homopolymer and the two polypropylene blends containing 10 and 25% of a polyethylene‐based elastomer. In the isotropic state, the blend containing 25% elastomer exhibited higher fracture toughness than the homopolymer and the 10% blend. The oriented sheets were tested both parallel (cracks perpendicular to the draw direction) and perpendicular (cracks parallel to the draw direction). For the latter case of cracks parallel to the draw direction, the fracture toughness of all the materials decreased with increasing draw ratio and up to a draw ratio of 4 the 25% blend exhibited higher fracture toughness than the other two materials. At higher draw ratios, however, the unfilled polypropylene was tougher than the blends. When tested parallel to the draw direction, all three materials failed with the cracks growing slowly initially followed by sudden rupture. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 1336–1345, 2003
Thermal properties of poly(vinyl alcohol)/poly(diallyldi‐methylammonium chloride) interpenetrating polymer networks
Authors: Kim Seon Jeong , Yoon Seoung Gil , Lee Young Moon , Kim In Young , Kim Sun I.
Published: February 2003

Interpenetrating polymer networks (IPNs) constructed with poly(vinyl alcohol) (PVA) and poly(diallyldimethyl ammonium chloride) (PDADMAC) using a sequential IPN method were prepared. The thermal characterization of the IPNs was investigated by differential scanning calorimetry (DSC), dielectric analysis (DEA), and thermogravimtric analysis (TGA). Decreases in the melting temperature of PVA segments in IPNs were observed with increasing PDADMAC content using DSC. DEA was employed to ascertain glass transition temperature of IPNs. The thermal decomposition of IPNs was investigated using TGA, and thermal decomposition of IPNs could be decelerated by changing PVA content. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 1346–1349, 2003
Synthesis and characterization of novel soluble alternating copoly(phenylene vinylene) derivative for light‐emitting electrochemical cell
Authors: Xiang Dong , Shen Qundong , Zhang Suyang , Jiang Xiqun
Published: February 2003

A novel alternating copolymer, poly{[2,5‐di(2‐(2‐ethoxy ethoxy)ethoxy)‐1,4‐phenylene vinylene]‐alt‐1,4‐[phenylene vinylene]}, has been synthesized through the Wittig condensation as electroluminescent material. In this copolymer, one component is phenylene vinylene with flexible oligo(ethylene oxide) side chain that facilitates ion transportation and phase miscibility between nonpolar and polar part of composite luminescent layer, and another is a rigid phenylene vinylene moiety to improve luminescent quantum efficiency and tune color. The copolymer shows good solubility and thermal stability for device fabrication compared to poly(phpeylene vinylene)(PPV). The band gap value of copolymer is between those of corresponding homopolymers, which indicates that alternating copolymerization is a suitable way to obtain luminescent polymer with desired band gap. The maximum wavelength of photoluminescence of copolymer is 539 nm (yellowish‐green). The HOMO and LUMO energy levels obtained by cyclic voltammetry measurement indicate that the electron injection ability of copolymer has been greatly improved compared with that of the PPV. A more balanced carrier injection and higher quantum efficiency are proved by electroluminescent properties of corresponding light‐emitting devices. The turn‐on voltage of LEC device (ITO/copolymer + PEO + LiClO4/Al) is found to be 2.3 V, with current comparative to LED (ITO/copolymer/Al) at 9.5 V. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 1350–1356, 2003
Structural development of poly(ethylene 2,6‐naphthalene dicarboxylate) film upon solvent drawing
Authors: Kang Young Ah , Kim Kyoung Hou , Lee Yang Hun , Lee Jang Oo , Cho Hyun Hok
Published: February 2003

To investigate the effect of “chemical energy” by solvent on structural development, initially molded amorphous poly(ethylene 2,6‐naphthalene dicarboxylate) (PEN) films were drawn in various solvent systems and at the optimum temperatures deliberately determined, and the resulting fine structure and properties were analyzed by using several experimental techniques. Water, 1‐butanol, 1,4‐dioxane/water (20 : 80 by volume), and 1,4‐dioxane/1‐butanol (20 : 80 by volume) were chosen for drawing solvent. For this study, in view of chemical structure and solubility parameter, though, these are nearly immiscible or partially miscible liquids against PEN, with just the plasticizing actions more or less the primary concern here. Interesting enough, the temperature range near the main endothermic peak corresponding to the depressed boiling point of liquid caused by unfavorable interaction between PEN and solvent in mixtures of amorphous PEN film with various solvent systems, as determined by the DSC scans, was found to coincide with the optimum drawable range for each solvent system, over which several experiments, including the determination of maximum draw ratio (DRmax) have been carried out throughout the study. The experimental results obtained from this study could be explained, through qualitatively, in terms of the interactions between PEN and solvents. Hence, it is expected to control the fine structure and properties of PEN films resulting from the low‐temperature solvent drawing via a suitable choice of liquids and the corresponding draw temperature ranges. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 1357–1365, 2003
Swelling behavior of radiation‐polymerized polyampholytic two‐component gels: Dynamic and equilibrium swelling kinetics
Authors: Bhardwaj Y. K. , Kumar Virendra , Sabharwal S.
Published: February 2003

Polyampholytic hydrogels, with varying degrees of crosslinking and ionic content, were prepared by radiation polymerization of p‐sodium styrene sulfonate (SSS) and vinyl benzyl trimethylammoniumchloride (VBT). These gels were investigated for their dynamic and equilibrium swelling kinetics. Dynamic swelling of these gels established that the gels containing equal amounts of SSS and VBT strictly follow Fickian diffusion. The hydrogels containing excess of SSS followed the case II type of diffusion, whereas those containing excess of VBT followed anomalous diffusion. Equilibrium swelling kinetics of these gels in aqueous system, ethanol–water mixture, at different pHs, and in the presence of solutions of biological interest was studied. It was seen that gels containing equal amounts of SSS and VBT show the lowest equilibrium swelling. Swelling of the polyampholytic gel decreased with an increase in the radiation dose imparted and the amount of crosslinking agent incorporated in the gel. The gels having an excess of VBT showed higher equilibrium swelling in comparison to those having an excess of SSS. Differential scanning calorimetry (DSC) studies showed that crosslinking of the gels decreases equilibrium swelling but increases the bonded nonfreezable water content of the gels. The organic solvents like ethanol cause abrupt collapse of the polyampholyte gels containing excess of SSS and those containing equal amounts of both the monomers at some critical ratio of water and ethanol in swelling medium. However, the deswelling in the water–ethanol mixture was gradual for gels containing an excess of VBT and the extent of deswelling was also low for these gels in comparison to other gels. The swelled gels of all compositions deswelled when they were transferred to solutions at pH in the range 2–12. Biologically important solutes like urea, glucose, and surfactants like Triton‐X tend to further swell the polymer matrices, whereas NaCl causes their deswelling. The additive effect is more prominent for polyampholyte gels containing excess of either of the monomers. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 730–742, 2003
Synthesis and characterization of a novel phthalazinone poly(aryl ether sulfone ketone) with carboxyl group
Authors: Xuan Yingnan , Gao Yan , Huang Yong , Jian Xigao
Published: February 2003

Soluble, thermally stable phthalazinone poly(aryl ether sulfone ketone)s (PPESKs) containing a carboxyl group in its side chain have been synthesized by the nucleophilic displacement reaction of 4‐(4‐hydroxylphenyl)‐1(2H)‐phthalazinone with bis(4‐chlorophenyl) sulfone, 4,4′‐difluoro‐benzophenone, and phenolphthalin. The polymerization reactions were conducted in sulfolane in the presence of K2CO3 to give high molecular weight polymers, which are soluble in solvent such as nitrobenzene and pyridine at room temperature and easily cast into flexible, yellow, and transparent film. The polymers are amorphous with high glass transition temperature. The decomposition temperature of the polymers are >400°C, which indicates high thermal stability. The crosslinking reaction of PPESK can occur by using dicyandiamide (Dicy) as curing agent. The apparent energy (ΔE) is 52.2 kJ/mol and reaction order (n) is close to 1.0. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 1111–1114, 2003
Meta-analysis suggests antibiotic prophylaxis is not warranted in low-risk patients undergoing laparoscopic cholecystectomy
Authors: Al-Ghnaniem R , Benjamin I S , Patel A G
Published: February 2003

A financially important conclusion
Preoperative assessment of prognostic factors in rectal cancer using high-resolution magnetic resonance imaging
Authors: Brown G , Radcliffe A G , Newcombe R G , Dallimore N S , Bourne M W , Williams G T
Published: February 2003

Background

The aim was to determine the accuracy of preoperative magnetic resonance imaging (MRI) in the evaluation of pathological prognostic factors that influence local recurrence and survival in rectal cancer.

Methods

Ninety-eight patients undergoing total mesorectal excision for biopsy-proven rectal cancer were assessed prospectively using high-resolution MRI for tumour (T) and nodal (N) staging using the tumour node metastasis classification, depth of extramural tumour spread, the presence or absence of extramural venous invasion, a threatened circumferential resection margin and serosal involvement at or above the peritoneal reflection. Preoperative magnetic resonance assessment of these prognostic factors was compared with histopathological findings in carefully matched whole-mount sections of the resection specimen.

Results

There was 94 per cent weighted agreement (weighted κ = 0·67) between MRI and pathology assessment of T stage. Agreement between MRI and histological assessment of nodal status was 85 per cent (κ = 0·68). Although involvement of small veins by tumour was not discernible using MRI, large (calibre greater than 3 mm) extramural venous invasion was identified correctly in 15 of 18 patients (κ = 0·64). MRI predicted circumferential resection margin involvement with 92 per cent agreement (κ = 0·81). Seven of nine patients with peritoneal perforation by tumour (stage T4) were identified correctly using MRI.

Conclusion

High-resolution MRI of the rectum allows preoperative identification of important surgical and pathological prognostic risk factors. This may allow both better selection and assessment of patients undergoing preoperative therapy.
Evaluation of POSSUM and P-POSSUM scoring systems in patients undergoing colorectal surgery
Authors: Tekkis P P , Kessaris N , Kocher H M , Poloniecki J D , Lyttle J , Windsor A C J
Published: February 2003

Background

The Physiological and Operative Severity Score for the enUmeration of Mortality and morbidity (POSSUM) and Portsmouth POSSUM (P-POSSUM) equations were derived from a heterogeneous general surgical population and have been used successfully as audit tools to provide risk-adjusted operative mortality rates. Their applicability to high-risk emergency colorectal operations has not been established.

Methods

POSSUM variables were recorded for 1017 patients undergoing major elective (n = 804) or emergency (n = 213) colorectal surgery in ten hospitals. Subgroup analysis was performed to investigate the predictive capability of POSSUM and P-POSSUM in emergency and elective surgery and in patients in different age groups.

Results

The overall operative mortality rate was 7·5 per cent (POSSUM-estimated mortality rate 8·2 per cent; P-POSSUM-estimated mortality rate 7·1 per cent). In-hospital deaths increased exponentially with age. Both scoring systems overpredicted mortality in young patients and underpredicted mortality in the elderly (P < 0·001). Death was underpredicted by both systems for emergency cases, significantly so at a simulated emergency caseload of 47·9 per cent (P < 0·05).

Conclusion

There is a lack of calibration of POSSUM and P-POSSUM systems at the extremes of age and high emergency workload. This has important implication in clinical practice, as consultants with a high emergency workload may seem to underperform when these scoring systems are applied. Recalibration or remodelling strategies may facilitate the application of POSSUM-based systems in colorectal surgery.
Assessment of the accuracy of transrectal ultrasonography in anorectal neoplasia
Authors: Mackay S G , Pager C K , Joseph D , Stewart P J , Solomon M J
Published: February 2003

Background

Accurate preoperative staging of anorectal neoplasia is required to identify patients for whom local excision or adjuvant therapy may be appropriate. The objectives of this study were to review the accuracy of endoluminal transrectal ultrasonography (TRUS) in the staging of rectal cancers and to determine the learning curve before optimal staging accuracy can be achieved.

Methods

The results of all TRUS examinations for the assessment of anorectal neoplasia performed by two colorectal surgeons at two teaching hospitals of the University of Sydney from 1991 to 2001 were collected prospectively.

Results

Of the 433 patients examined by TRUS, 356 were included, of whom 263 (73·9 per cent) had nodal status assessed histologically. Of the 77 patients excluded, 50 had undergone radiotherapy before operation. TRUS achieved excellent accuracy when compared with histopathology reports using κ statistics for standard Union Internacional Contra la Cancrum (UICC) staging (κ = 0·89), tumour wall penetration (κ = 0·70), lymph node detection (κ = 0·66) and a proposed new staging system (κ = 0·94). In addition, the increase in TRUS accuracy with operator experience demonstrates the need to perform 50 or more procedures before optimal accuracy is achieved.

Conclusion

TRUS provides an appropriate investigation with which to select patients with T1 tumours for local excision, and patients with T3 or T4 tumours for preoperative radiotherapy. The relative inaccuracy of staging T2 tumours by TRUS has led to a proposed alternative ultrasonographic staging system.
Smoking affects the outcome of transanal mucosal advancement flap repair of trans-sphincteric fistulas
Authors: Zimmerman D D E , Delemarre J B V M , Gosselink M P , Hop W C J , Briel J W , Schouten W R
Published: February 2003

Background

The aim of the study was to identify variables affecting the outcome of transanal advancement flap repair (TAFR) for perianal fistulas of cryptoglandular origin.

Methods

Between 1995 and 2000, a consecutive series of 105 patients (65 women, 40 men), with a median age of 44 (range 19–72) years was included in the study. The patients were recruited from the colorectal departments of two university medical centres. Patients with a rectovaginal fistula and those with a fistula due to Crohn's disease were excluded. The following variables were assessed: age, sex, number of previous attempts at repair, preoperative seton drainage, fistula type, presence of horseshoe extensions, location of the internal opening, postoperative drainage, body mass index and the number of cigarettes smoked per day. The results were analysed by means of multiple logistic regression.

Results

The median follow-up was 14 months. No differences were observed between the two centres. TAFR was successful in 72 patients (69 per cent). None of the variables affected the outcome of the procedure, except for smoking habit of the patient. In patients who smoked the observed healing rate was 60 per cent, whereas a rate of 79 per cent was found in patients who did not smoke. This difference was statistically significant (P = 0·037). Moreover, a significant correlation was observed between the number of cigarettes smoked per day and the healing rate (P = 0·003).

Conclusion

Cigarette smoking affects the outcome of TAFR in patients with a cryptoglandular perianal fistula.
Prevention of pleural effusion following hepatectomy using argon beam coagulation
Authors: Kwon A-H , Matsui Y , Satoi S , Kaibori M , Kamiyama Y
Published: February 2003

Background

Postoperative pleural effusion occurs frequently after hepatectomy. The value of the argon beam coagulator (ABC) for the prevention of pleural effusion after hepatectomy in patients with hepatocellular carcinoma was studied.

Methods

Sixty patients were divided randomly into two groups: an ABC group (n = 28), in which the cut surface of the hepatic ligaments and bare area of the retroperitoneum were cauterized using an ABC, and a control group (n = 32) in which the ABC was not applied. Patient characteristics, preoperative and postoperative liver function, and postoperative pleural effusion were compared between the two groups.

Results

There were no significant differences between the two groups with respect to histological findings, clinical stage, type of resection, operative data, and preoperative and postoperative laboratory data. One of 28 patients in the ABC group and nine of 32 patients in the control group had pleural effusion. The incidence was significantly lower in the ABC group than in the control group (P = 0·01). Pleurocentesis was needed in two of the ten patients and thoracic drainage in four patients.

Conclusion

Application of an ABC to the cut surface of the hepatic ligaments and bare area of retroperitoneum after liver mobilization may prevent postoperative pleural effusion.
Moving from open to laparoscopic appendicectomy
Authors: Sweeney K J , Keane F B V
Published: February 2003

The argument in favour of laparoscopic appendicectomy
Insulin resistance in sepsis
Authors: Carlson G L
Published: February 2003

Basic understanding of the phenomenon remains elusive
Interstitial ablative techniques for hepatic tumours
Authors: Erce C , Parks R W
Published: February 2003

Background

Most patients with liver tumours are not suitable for surgery but interstitial ablative techniques may control disease progression and improve survival rates.

Methods

A review was undertaken using Medline of all reported studies of cryoablation, radiofrequency ablation, microwave ablation, interstitial laser photocoagulation, high-intensity focused ultrasound and ethanol ablation of primary liver tumours and hepatic metastases.

Results

Although there are no randomized clinical trials, cryoablation, thermal ablation and ethanol ablation have all been shown to be associated with improved palliation in patients with primary and secondary liver cancer. The techniques can be undertaken safely with minimal morbidity and mortality.

Conclusion

Although surgical resection remains the first line of treatment for selected patients with primary and secondary liver malignancies, interstitial ablative techniques are promising therapies for patients not suitable for hepatic resection or as an adjunct to liver surgery.
Increased secretion of insulin during oral glucose tolerance test can be a predictor of stent restenosis in nondiabetic patients
Authors: Babalık Erhan , Gürmen Tevfik , Orhan Lütfullah , Bulur Hüseyin , Gülbaran Murat , Ersanlı Murat , Öztürk Servet
Published: February 2003

Insulin is known to stimulate proliferation and migration of vascular smooth muscle cells. As the predominant mechanism of restenosis after stent implantation is neointimal tissue proliferation, one can expect a relationship between hyperinsulinemia and restenosis in these patients. The aim of this study was to determine whether hyperinsulinemia during oral glucose tolerance test is a predictor of the development of restenosis after stent implantation in nondiabetic patients. We prospectively studied 52 nondiabetic patients with effort angina who underwent elective stent implantation for single‐vessel coronary artery disease. In order to increase the statistical power of the study, numerous exclusion criteria were applied. All patients were subjected to a 75 g oral glucose tolerance test a day before the stent implantation and underwent follow‐up angiography 6 months later. Plasma insulin levels in fasting (6.77 ± 1.57 vs. 5.36 ± 1.35 μU/ml; P = 0.005), at 30 min (102.48 ± 10.6 vs. 47.74 ± 12.75 μU/ml; P = 0.001), 1 hr after (120.23 ± 14.1 vs. 63.08 ± 12.62 μ/ml; P = 0.001), 2 hr after (63.58 ± 8.64 vs. 34.88 ± 6.82 μ/ml; P = 0.001), and 3 hr after (25.71 ± 5.65 vs. 23.02 ± 4.61 μ/ml; P = 0.04) loading were significantly higher in patients with stent restenosis than in patients without stent restenosis. Insulin area and insulin area/glucose area were also significantly higher in patients with stent restenosis than in patients without (219.5 ± 23.8 vs. 118.9 ± 21.8, P = 0.001, and 0.62 ± 0.09 vs. 0.33 ± 0.06, P = 0.001, respectively). By multiple logistic regression analysis, insulin area during oral glucose tolerance test was found to be an independent predictor of stent restenosis (OR = 1.12; 95% CI = 1.01–1.25; P = 0.031). In conclusion, nondiabetic patients with hyperinsulinemia during oral glucose tolerance test have a high risk for restenosis after stent implantation, and performing this simple test before intervention may be useful for the prediction of stent restenosis. Cathet Cardiovasc Intervent 2003;58:306–312. © 2003 Wiley‐Liss, Inc.
Intracoronary beta‐brachytherapy in chronic total occlusions: A subgroup analysis from the RENO registry
Authors: Jain Deepak , Geist Volker , Lorenzen Hans‐Peter , Hartmann Franz , Wegscheider Karl , Bonan Raoul , Urban Philip , Richardt Gert
Published: February 2003

Conventional interventional therapy has been less rewarding in chronic total occlusion (CTO). Brachytherapy by its antiproliferative and positive remodeling effect may be more efficacious. Forty‐six centers registered 1,098 consecutive patients undergoing brachytherapy with the BetaCath system. Of these, 78 patients had 82 lesions (CTO) at presentation—the study population. With 67% in‐stent CTO, 8% graft CTO, 4% recurrent CTO, long lesions (27.6 ± 20.9 mm), and 31% diabetes, the cohort had high risk for recurrence. The in‐hospital event rate was 1.3%. Six‐month follow‐up revealed 1.3% death, 5.1% myocardial infarction, 21.8% target vessel revascularization, 77.8% improved angina, 34.5% binary restenosis, 12.7% reocclusion, and 10.3% late thrombosis. The results were comparable to all other patients in the registry, although late thrombosis rate was higher in the CTO group (10.3% vs. 5.0%; P = 0.047). In the in‐stent CTO subgroup (n = 52; 66.7%), there was no in‐hospital event, no follow‐up death or myocardial infarction, restenosis in 35.1%, and reocclusion in 10.8% of patients. In comparison, death or myocardial infarction was significantly higher in de novo CTO subgroup (P = 0.005). Compared to all other in‐stent restenosis patients in the registry, the patients with in‐stent CTO had similar clinical and angiographic event rate. Thus, beta‐brachytherapy was safe, feasible, and effective in this broad population of high‐risk patients with CTO presenting in day‐to‐day practice. It was particularly effective in in‐stent CTO, where conventional interventional strategies are disappointing. Cathet Cardiovasc Intervent 2003;58:322–329. © 2003 Wiley‐Liss, Inc.
Influence of stent treatment strategies in the long‐term outcome of patients with long diffuse coronary lesions
Authors: Pan Manuel , Suárez de Lezo José , Medina Alfonso , Romero Miguel , González Sandra , Segura José , Pavlovic Djordje , Rodríguez Marcos , Muñoz Juan , Ojeda Soledad , Hernández Enrique , Caballero Eduardo , Delgado Antonio , Melián Francisco
Published: February 2003

Diffuse coronary lesions (length > 20 mm) are still considered high risk for percutaneous intervention even in the current stent era. We compared the 2‐year outcome of patients with long diffuse stenosis treated by three different stent strategies. In addition, we also analyzed the possible factors influencing a favorable late outcome. Our series is constituted by 232 patients with 247 long lesions treated between May 1994 and April 1999; 82 patients received one single long stent (group 1), 71 patients were treated by overlapped multiple stents (group 2), and 79 with multiple nonoverlapped stents (group 3). The mean age was 59 ± 11 years. There were not significant differences between groups in terms of age, risk factors, clinical presentation, type of lesion, or adjunctive medical therapy. Patients from group 1 had shorter lesions (29 ± 10 mm) than patients from groups 2 (41 ± 15 mm) and 3 (36 ± 14; P < 0.05). Major cardiac events (death, acute myocardial infarction, or repeat revascularization) at 24 ± 12 months follow‐up took place in 39 patients (17%). The probabilities of being free of major events at follow‐up were 71%, 78%, and 80% for group 1, 2, and 3 respectively (P = NS). Only three variables were identified as significant predictors of these late events: smaller vessel size, smaller minimal lumen diameter after stenting, and the type of lesion being restenotic as compared with native stenosis. Patients with diffuse lesions treated by single long stents did not have a better late outcome than those who received multiple stents. The best late outcome was observed in those patients who had bigger vessel size, larger poststent lumen dimensions and native lesions, regardless of the stent deployment strategy used. Cathet Cardiovasc Intervent 2003;58:293–300. © 2003 Wiley‐Liss, Inc.
Use of filterwire EX for distal embolic protection during complex percutaneous coronary interventions: Four case studies
Authors: Kornowski Ran , Assali Abid
Published: February 2003

We describe four successful cases demonstrating the use of a novel filter‐guidewire (FilterWire EX) during complex percutaneous coronary interventions in saphenous vein grafts (n = 3) and native coronary artery (n = 1) for prevention of distal embolization and consequently myonecrosis. Cathet Cardiovasc Intervent 2003;58:364‐369. © 2003 Wiley‐Liss, Inc.