bluuebunny/crossref_metadata_2025 huggingface dataset:
Synthesis of vinyl phenyl acetate and an evaluation of vinyl chloride/vinyl phenyl acetate copolymers
Authors: Rees Gwilym J.
Published: April 2003

The synthesis of vinyl phenyl acetate, by an ester interchange reaction between phenyl acetic acid and vinyl acetate and utilizing a catalyst, is described. Copolymerization with vinyl chloride, in a suspension system and using a peroxide catalyst, is described on a laboratory and pilot plant scale. Monomer/copolymer compositions, for an initial charge consisting of vinyl chloride/vinyl phenyl acetate (80/20 by weight) are presented over a range of conversions, as an indication of reactivity ratios. Discs, molded from unstabilized copolymers, show very good clarity and color stability, which improve with increased comonomer loading. Some retention of unpolymerized vinyl phenyl acetate monomer occurred, and some increase in softening points resulted following two reprecipitations from acetone into excess methanol. Compound from a 96/4 vinyl chloride/vinyl phenyl acetate copolymer has better color stability than does an equivalent vinyl chloride/vinylidene chloride copolymer compound. The enhanced color and heat stability of the copolymers is attributed to the aromatic character of the comonomer vinyl phenyl acetate.
Interfacing polypropylene/poly(BPA carbonate) blend phases with graft copolymers: Thermal and dynamic mechanical analyses
Authors: Liang Zhizhong , Williams H. Leverne
Published: April 2003

This paper presents data on the thermal, dynamic, and mechanical properties of polypropylene (PP) blends with bisphenol‐A‐polycarbonate (PC), to which a series of graft and block copolymers in a small quantity was added. The effect of the minor component on the crystallization and relaxation behavior of PP in the blends has been investigated and correlated with the mechanical properties obtained. The results demonstrate that the graft copolymeric additives to the blends can reduce the degree of undercooling (Tm°C − Tc°C) of the PP phase. However, the block copolymers used, substituting for the graft copolymers, showed no such function. Dynamic mechanical thermal analysis (DMTA) indicates that, with the addition of several different copolymers as minor additives to the blends, two loss peaks representing the glassy transitions (Tg) of the individual components (PP and PC) were retained, with little tendency of approaching toward each other, suggesting no obvious improvement in compatibility of the PP phase and the PC phase in the blends. Nevertheless, the inclusion of different copolymers in the PP/PC blends, in spite of the small quantity used (4%), can lead to a significant mechanical property difference of the blends. This difference could be reasonably explained from the data obtained in dynamic mechanical characterization of the different graft copolymers in PP blends.
Combined processing of polypropylene film by coextrusion and zone‐annealing
Authors: Kunugi Toshio , Yoneyama Yuko , Suzuki Akihiro , Porter Roger S.
Published: April 2003

In order to improve the mechanical properties of polypropylene film, a new processing combining extrusion and zone‐annealing has been applied. It was found that there are suitable conditions for each step in the combined processing. When the coextrusion draw ratio was low, the total draw ratio and modulus could be increased by the zone‐annealing subsequently done. The highest modulus was obtained when the film was coextruded at extrusion draw ratio 4 and then zone‐annealed at 120°C under 7 kg/mm2. The value was 12 GPa in Young's modulus or 17 GPa in dynamic modulus. The peak temperature of αc dynamic dispersion for the combinedly processed film was 109°C, which is higher by 10°C than that for the as‐coextruded film. Four drawing methods were compared in dynamic viscoelasticity. These methods are the coextrusion, zone‐drawing/zone‐annealing, two‐step coextrusion, and the combined processing by coextrusion and zone‐annealing. The highest dynamic modulus for each method was arranged in the above order. The combined processing indicated the most effective improvement in mechanical properties, because it is believed that lamellae in the original film were broken by cooperating interaction of shear stress, compression, and tension on coextrusion and then the superstructure with a high crystallinity and a high molecular orientation was formed on zone‐annealing.
The structure of never‐dried cotton fibers
Authors: Ishaq A. , Peacock N.
Published: April 2003

The X‐ray photographs of fresh never‐dried cotton fibers are compared with those of dried fibers. The crystallite size of never‐dried cotton fibers shows no significant correlation with maturity and orientation and is about the same as those of dried cotton fibers.
Toughening of epoxy resins by modification with aromatic polyesters
Authors: Iijima Takao , Tomoi Masao , Tochimoto Takuya , Kakiuchi Hiroshi
Published: April 2003

Aromatic polyesters, prepared by the reaction of phthalic or isophthalic acids and α,ω‐alkanediols, were used to reduce the brittleness of bisphenol‐A diglycidyl ether epoxy resin cured with methyl hexahydrophthalic anhydride. These polyesters were effective as modifiers for toughening of the epoxy resin system. The most suitable composition for modification of the epoxy resins was inclusion of 20 wt % of poly(ethylene phthalate) (MW 7200), which resulted in a 150% increase in the fracture toughness (KIC) of the cured resin at no expense of its mechanical properties. The effectiveness of poly(alkylene phthalate)s as modifiers decreased with increasing the chain length of alkylene units. The toughening mechanism was discussed based on the morphological and dynamic mechanical behaviors of the modified epoxy resin system.
Multifrequency analysis of the α relaxation region of high‐density polyethylenes: Influence of thermal history
Authors: Orozco Jose A. Gonzalez , Rego Jose M. , Katime Issa
Published: April 2003

The activation energy analysis of the dynamic‐mechanical α relaxation has been carried out as a function of thermal history for several high‐density polyethylenes. The air‐quenched samples display a unique α relaxation whose temperature dependence fits a constant activation energy regardless of the structural features of the samples, whilst the isothermally crystallized samples, on the other hand, display an asymmetric α peak that, often, splits into two, which does not fit a constant activation energy. The asymmetry of the α peak as well as the splitting has been explained accounting for two different relaxation time distributions. The dependence of the intensity of the α and α′ relaxations on frequency have been discussed in terms of different mean relaxation times and amorphous layer thickness.
Physical and mechanical properties of henequen fibers
Authors: Cazaurang‐Martinez M. N. , Herrera‐Franco P. J. , Gonzalez‐Chi P. I. , Aguilar‐Vega M.
Published: April 2003

A study of morphology, physical, and mechanical properties of henequen (Agave fourcroydes) fibers have been performed in this article. It has been concluded that properties of the fibers are more uniform in their middle section. As other natural hard fibers, henequen has a relative high tenacity, low elongation at break and a low modulus. These properties suggest that the fiber could be used as reinforcing agent in composite materials.
Synthesis of polymers with long side chain of N‐alkyl esters and their effects on pour‐point depression of oil
Authors: Huiyang Zeng , Weibang Zhang , Zhuomei Li
Published: April 2003

Three poly(n‐alkyl acrylates), PA‐14, PA‐16, and PA‐18, and three poly(vinyl alcohol) aliphatic acid esters, PVA‐14, PVA‐16, and PVA‐18, have been synthesized. They are white crystalline polymers at room temperature and characterized by IR, DSC, SALLS‐photometer, and polarizing microscope. Both the melting point and heat of fusion of PVA–esters are larger than those of the corresponding PA–esters, and the sizes of spherulites of PVA–esters are also larger. This may be attributed to the different order of linking in the ester group and the OH group residue in PVA–esters. In the testing of the effects on pourpoint depression of some petrolic oils, only PA‐14 and PVA‐14 are effective for 0# diesel oil. The influences of molecular weight and molecular weight distribution of PA–esters and PVA–esters upon the pour‐point depression of oil are negligible. These results show that the length of n‐alkyl side chain of the polyesters plays the most important role in depressing the pour‐point of petrolic oil and that the order of linking in the esters group seems to be in no relation to this effect.
PVT scaling parameters for polymer melts. II. Error in all variables
Authors: Hartmann Bruce , Simha Robert , Berger Alan E.
Published: April 2003

An algorithm is discussed for determining best‐fit scaling parameters in the PVT equation of state of polymer melts from experimental data. The underlying theoretical expressions are those employed in our preceding work. There it was assumed that values of pressure and temperature are known exactly and experimental uncertainty was admitted in the volume solely. This condition is now relaxed to allow for errors in P and T also. The methodology developed involves multiple small nonlinear fitting problems for two or three unknowns at a time. We employ it on the experimental data base in the earlier work, which consists of 11 polymer melts. To these is added ethylene monomer, analyzed earlier by Nies et al. by different methods. The numerical values of the scaling parameters differ by at most a fraction of a percent from those in the earlier computations and enhance the accuracy of fit but slightly. The significant improvement over the consecutive procedure (analysis of atmospheric pressure isobar, followed by isotherms at elevated pressures), seen earlier, continues therefore. The scaling parameters so obtained should represent the ultimate in computational accuracy consistent with a specified experimental accuracy. This may have a bearing ultimately on the issue of modeling molecular characteristics, expressed through the scaling parameters, versus macroscopic properties. Using the parameters determined here, it is shown that the entropy is correlated with the scaling temperature and that the flexibility parameter is related to polymer complexity.
Sag equation for coatings on rotating substrates
Authors: Frisch H. L. , Scopazzi C.
Published: April 2003

We develop the sag length equation for coatings on rotating substrates, neglecting Coriolis force effects. The equation is integrated analytically for both Newtonian and some cases of non‐Newtonian flow. For rotating substrates, the sag in one direction is compensated for by sag in the opposite direction, and unlike the nonrotating case, the sag is not proportional to time.
Structural effect of the microgels with a core‐shell morphology synthesized from poly(α‐methylstyrene‐b‐methyl methacrylate) on the swelling behavior of the microgel
Authors: Saito Reiko , Ishizu Koji , Fukutomi Takashi
Published: April 2003

The swelling behavior of the core‐shell microgels [32 mol % poly(methyl methacrylate) (PMMA) core and 68 mol % poly(α‐methylstyrene) (PMeSt) shell], the random mixing microgels with 32 mol % PMMA and 68 mol % PMeSt, and the PMMA microgels was investigated in two solvent systems (toluene/n‐hexane and benzene/n‐butanol) by turbidimetric titrations from the viewpoint of the structural effect of the microgels. All coreshell microgels did not precipitate in the solvent in which the material block copolymer had perfectly precipitated. For the core‐shell microgels, the flat regions appeared on the way to perfect turbidity. From the measurement of the composition of the solvent swollen in the polymers and the microgels, it was determined that these anomalous phenomena were due to the properties of the polymer micelles in the core‐shell microgels.
Diffusion and subsequent polymerization of styrene in oriented polypropylene matrix
Authors: Trznadel M. , Milczarek P. , Kryszewski M.
Published: April 2003

Results of investigations of styrene diffusion into oriented polypropylene matrix and subsequent polymerization performed in special conditions are shown for samples drawn at various temperatures to different draw ratios. It is demonstrated that styrene sorption in oriented polypropylene is relatively low, but proposed processing leads to obtaining polypropylene–polystyrene composities with large polystyrene contents.
Interpenetrating polymer network of poly(vinyl chloride) and polymethacrylates
Authors: Abu‐Isa Ismat A.
Published: April 2003

A curable polymeric composite was prepared using equal weights of poly(vinyl chloride) (PVC), reactive polyfunctional methacrylate monomers, and inorganic fillers. Peroxide initiated in situ polymerization of the polyfunctional methacrylate monomers in the PVC matrix produced an interpenetrating polymer network (IPN) structure. The polymerization kinetics and the degree of polymerization were investigated using differential scanning calorimetry (DSC), carbon‐13 nuclear magnetic resonance (13C NMR), and solvent extraction. All measurements indicated that during polymerization, the PVC is either crosslinked by or grafted onto the methacrylate three‐dimensional network structure. The rheological properties of the composite were measured before curing using a Rheometrics mechanical spectrometer and found to exhibit mainly viscous behavior and diminished elasticity. The PVC and the methacrylate monomers form a two‐phase system when mixed at room temperature. However, when heated to 100°C the PVC dissolves in the monomers and forms a one‐phase optically clear blend with a single glass transition temperature. In the presence of peroxide, the one‐phase blend is stable and does not separate out upon cooling and storing at room temperature.
Identification of styrene copolymers and a terpolymer by second derivative ultraviolet spectroscopy
Authors: Meal Larie
Published: April 2003

A method for distinguishing styrene copolymers and a terpolymer by second derivative ultraviolet spectroscopy will be described. The polymers were dissolved in chloroform except for one which was dissolved in 2‐butanone. Concentrations of about 5 g/L were used. The polymer solutions were applied to the removable windows of divided, quartz cells and were allowed to dry to a thin film. The ultraviolet region was scanned from 300 to 230 nm. Then thinner films were used, and the 240–200 nm region was scanned. The second derivative spectra that resulted could be distinguished easily. This technique allows rapid, sample preparation and identification of these copolymers and the terpolymer.
Chemical modification of poly(substituted‐acetylene). VI. Introduction of fluoroalkyl group into poly(1‐trimethylsilyl‐1‐propyne) and the improved ethanol permselectivity at pervaporation
Authors: Nagase Yu , Sugimoto Kikuo , Takamura Yuriko , Matsui Kiyohide
Published: April 2003

In order to improve the separation characteristics of membranes for pervaporation, the introduction of fluoroalkyl groups into poly(1‐trimethylsilyl‐1‐propyne) (PTMSP) was achieved by two methods. First, 3,3,3‐trifluoropropyldimethylsilylated PTMSP was prepared via metalation of PTMSP followed by treating with 3,3,3‐trifluoropropyldimethylchlorosilane. About 6 mol % of 3,3,3‐trifluoropropyldimethylsilyl group was introduced by the polymer reaction. Second, the copolymerizations of 1‐trimethylsilyl‐1‐propyne (TMSP) with 1‐ (3,3,3‐trifluoropropyldimethylsilyl)‐1‐propyne (FPDSP) or 1‐ (1H,1H,2H,2H‐tridecafluorooctyldimethylsilyl)‐1‐propyne (FODSP) were carried out to afford TMSP/FPDSP or TMSP/FODSP random copolymers. The ratio of TMSP monomer unit and the comonomer unit, x/y, was in the range of 99/1‐85/15. All the chemically modified PTMSP membranes showed ethanol permselectivity for pervaporation of aqueous ethanol solution. In particular, the introduction of less than about 5 mol % of fluoroalkylsilylated units into PTMSP effectively enhanced the selectivity. However, excess introduction of FODSP comonomer unit caused a decrease of the selectivity, with the value being smaller than that of PTMSP membrane. Furthermore, tetrahydrofuran, acetone, acetonitrile, dioxane, and isopropanol were efficiently separated from their dilute aqueous solutions using a TMSP/FPDSP copolymer membrane.
Material design for polymer/azobenzene liquid crystal/metal salt composite films possessing thermo‐ and photoresponsive ionic conductivity
Authors: Kimura Keiichi , Morooka Hisashi , Yokoyama Masaaki
Published: April 2003

Various azobenzene derivatives and polymers were attempted as materials for thin composite films containing a polymer, a liquid crystal, and lithium perchlorate which can undergo ionic‐conductivity switching induced by light or heat. Poly(vinyl chloride) ‐based composite films containing enantiotropic azobenzene liquid crystals 1, exhibited significant ionicconductivity change based on thermo‐ and photoinduced phase transitions of 1, the temperature dependence on the ionic conductivity reflecting the enantiotropic phase transition behavior of the liquid crystals. Marked, reversible ionic‐conductivity switching on alternating irradiation of UV and visible lights was attained with the composite films containing 1, especially 1 (n = 12). Incorporation of monotropic liquid crystals 3 to the composite films allowed bistability in the temperature dependence on the ionic conductivity. Employment of a polycarbonate resin and poly(methyl methacrylate) as the polymer material of the composite films gave similar ionic‐conductivity changes to the poly(vinyl chloride) composite films, whereas polyethyleneoxide brought about some different results in the photoinduced ionic‐conductivity change.
Optically controlled ligand delivery. II. Copolymers containing α‐methylphenacyl bonds
Authors: Yen Hung‐Ren , Andrade Joseph D. , Kopeček Jindřich
Published: April 2003

N‐(2‐hydroxypropyl) methacrylamide copolymers containing side chains terminated in a model ligand, N‐tert‐butyloxycarbonylglycine (Boc‐Gly), bound via photocleavable α‐methylphenacyl bonds were synthesized to test the possibility of developing an optically controlled ligand delivery system suitable for sensors. One of the copolymers was further covalently attached to 3‐aminopropyl triethoxy silane (APS) coated porous silica beads which were modified with an excess of α,ω‐diaminopoly(ethylene oxide), molecular weights 1000 or 5000. The photochemical release of ligand induced by exposure to light in solution and at the solid‐liquid interface was studied. The influence of solvent and the length of poly(ethylene oxide) (PEO) spacers on the rate of photocleavage were determined. The hydrolytic stability of the α‐methylphenacyl bond in both solution and at the solid‐liquid interface were also investigated.
Miscibility of poly(2‐chloroethyl methacrylate) with various polymethacrylates
Authors: Neo M. K. , Lee S. Y. , Goh S. H.
Published: April 2003

The miscibility behavior of poly(2‐chloroethyl methacrylate) (PCEMA) with various polymethacrylates was investigated by differential scanning calorimetry. PCEMA is miscible with poly(methyl methacrylate) (PMMA), poly(ethyl methacrylate) (PEMA), and poly(tetrahydrofurfuryl methacrylate) (PTHFMA), but is immiscible with poly(n‐propyl methacrylate), poly(isopropyl methacrylate), poly(n‐butyl methacrylate), and poly(cyclohexyl methacrylate). PCEMA/PEMA blends showed lower critical solution temperature (LCST) behavior but PCEMA/PMMA and PCEMA/PTHFMA blends degraded before phase separation could be induced. The miscibility behavior of PCEMA is similar to that of a chlorinated polymer.
Effects of some phenylethynylsilicon compounds on heat‐curable silicone rubber. I. 1,3‐bis(methylphenylethynylvinyl)disiloxane
Authors: Feng Shengyu , Du Zuodong
Published: April 2003

We have investigated the effects of 1,3‐bis (methylphenylethynylvinyl) disiloxane (BMPVDS) as crosslinker on heat‐curable silicone rubber and measured sol fractions and crosslink density of vulcanizates by benzene‐extract and toluene‐swelling methods, respectively. The experimental results show that, adding suitable amounts of BMPVDS, the vulcanizates exhibited rather fine mechanical properties. The tear strength of some vulcanizates could reach as high as 60.31 kN/m, the tensile strength 13.46 MPa, and the modulus at 100% extension 2.45 MPa, and the permanent deformation is rather low. BMPVDS is also a good curing retarder of hydrosilation curing silicone rubber. When adding 0.08 part of BMPVDS or more, the stocks can store at 20 ± 1°C more than 50 days without curing.
Removal of Escherichia coli from water by systems based on insoluble polystyrene–poly(ethylene glycol)s, –polyethylenimines, and –polyethylenepolyamines quaternized
Authors: Tashiro Tatsuo
Published: April 2003

Insoluble polymers adsorbing bacterial cells were prepared by reactions of chloromethylated, divinylbenzene crosslinked polystyrene (CMPS) beads with poly(ethylene glycol) 600 (PEG600), PEG monolaurate (PEGLE), polyethylenimines (PEIs, MW = ca. 300. 600. and 1200, referred to as PEI300, PEI600, and PEI1200, respectively), as well as ethylenediamine (ED) and tetraethylenepentamine (TEP) as polyethylenepolyamines. CMPS‐ED and CMPS‐TEP were further quaternized with 1‐iodooctane (IO) and 1‐iodododecane (IDD), respectively. These polymers were brought into contact with Escherichia coli by stirring in sterilized, distilled, and deionized water. Although CMPS‐PEG and CMPS‐PEGLE did not adsorb the cells, they caused a decrease in the number of viable cells. The decrease seemed to result from the bactericidal action of substances leached from the polymers. CMPS‐PEI300, CMPS‐PEI600, and CMPS‐PEI1200, CMPS‐ED‐IO, and CMPS‐TEP‐IDD caused a decrease in the viable cell number by adsorption of the cells to their surfaces. It was observed with a scanning electron microscope that the cells were present on the surfaces of CMPS‐PEI600 beads. The decrease coefficient for decrease in viable cell number of E. coli caused by the polymer increased with nitrogen content of the polymer. The adhesion of the cells to CMPS‐PEI300, CMPS‐PEI600, and CMPS‐PEI1200, CMPS‐ED‐IO, and CMPS‐TEP‐IDD was due mainly to electrostatic interaction between them.
The structure and properties of drawn blends of polyethylene and polypropylene
Authors: Gallagher G. A. , Jakeways R. , Ward I. M.
Published: April 2003

A series of highly oriented tapes has been prepared from a blend consisting of equal proportions of polyethylene and polypropylene. The mechanical properties and the structure and morphology of the samples have been investigated using DSC, optical microscopy, and wide angle and small angle diffraction, including measurements of crystal strain on samples under stress. It has been confirmed that the blend is incompatible, and a structural model has been proposed which is consistent with the observation that the polyethylene and polypropylene components act essentially independently in their response to external macroscopic stress.
Plasma deposition modified nylon 4 membranes for hemodialysis
Authors: Lai J. Y. , Shih C. Y. , Tsai S. M.
Published: April 2003

The purpose of this research is to prepare high solute permeability membranes for hemodialysis by plasma depositing hydrophilic monomers onto chemically treated or O2 plasma etched Nylon 4 substrate. The factors that affect the performances of membranes, such as deposition conditions and chemical or plasma etching conditions, were studied. The monomers used in this study were 1‐vinyl‐2‐pyrrolidone (VP), 2‐Hydroxyethyl methacrylate (HEMA), and Methyl methacrylate (MMA). The permeabilities of NaCl, urea, vitamin B12, and albumin were measured, as were the water content, hydration, diffusivity, partition coefficient, and protein adsorption ratio of fibrinogen to albumin by membrane surface of plasma deposited membranes.

The permeabilities of NaCl, urea, vitamin B12, and albumin of HEMA 5 w‐1 h plasma deposited onto chemical treated Nylon 4 membranes were 2.896 ± 0.192, 3.301 ± 0.325, 0.010 ± 0.007, and 0.000 x 10−5 cm2/min, respectively. The mole ratio of adsorbed fibrinogen to adsorbed albumin (F/A) is 0.26 ± 0.05, which is much lower than that of the pure Nylon 4 membrane (0.94 ± 0.06) and the Gambro® membrane (0.90 ± 0.15). The HEMA deposited membrane possesses the highest feasibility as hemodialysis material among those plasma deposited membranes considered.
Ultrasonic investigation of some rubber blends
Authors: Sidkey M. A. , El Fattah A. M. Abd , Yehia A. A. , El All N. S. Abd
Published: April 2003

Compression ultrasonic velocity, longitudinal ultrasonic absorption, and heat of mixing for NR‐BR, NR, NBR, and NR‐IIR rubber blends were measured. Results show the applicability of examining the compatibility degree by using longitudinal ultrasonic absorption techniques. Results showed that NR‐BR blends are compatible, whereas NR‐NBR and NR‐IIR blends are semicompatible and incompatible, respectively.
Interactions between polymeric containers and their contained solution: Modeling of polymer‐water solute partitioning via coupled solvent‐water partition coefficients
Authors: Jenke Dennis R. , Kenley Richard A. , Hayward Denise S.
Published: April 2003

The interaction between several polymeric materials, typical of those that have application as parenteral product containers, and 16 marker solutes was evaluated. Polymers used included polypropylene, polyvinyl chloride, ethylenevinyl acetate, an olefin rubber, a polyester ether block copolymer, and various composites of these materials. In addition, the partitioning of solutes between two common PVC plasticizers (dioctyl phthalate and butyryl hexyl citrate) and water was also examined. Correlation between equilibrium interaction constants (Eb) (which describe the equilibrium distribution of a solute between contacting polymer and solution phases) and solute octanol‐water (Po‐w) or hexane‐water (Ph‐w) partition coefficients were in general poor for all materials studied. However, a bivariate linear interaction model relating Eb to both partition coefficients:

effectively mimicked the interaction behavior of all materials evaluated. The utilization of the developed models to facilitate container compatability assessments is discussed. In addition, the use of a critical ratio of binding constants for a pair of solutes is introduced as a means of qualitatively assessing the effectiveness of a particular solvent as a polymer model.
Synthesis and characterization of ethyl methacrylate‐acrylamide copolymers
Authors: Srinivasulu B. , Rao P. Raghunath , Sundaram E. V.
Published: April 2003

Free radical copolymerization of ethyl methacrylate (EMA) and acrylamide (AA) was carried out in the presence of 2,2′‐azobisisobutyronitrile (AIBN) in dimethyl formamide (DMF) at 60°C. The percentage composition of the copolymers were established by elemental analysis. The copolymerization reactivity ratios were determined by both Fineman‐Ross (F‐R) and Kelen‐Tudos (K‐T) methods. The copolymers were characterized by IR, 1H‐NMR, thermal, and dielectric studies. Glass transition temperatures (Tg) have been determined by DSC. The solubility parameter of this copolymer was evaluated by studying the intrinsic viscosity in different solvents.
Polyimides synthesized from siloxane‐equilibrated 1,3‐bis (3,4‐dicarboxyphenyl)‐1,1,3,3‐tetramethyldisiloxane dianhydride
Authors: Nye S. A. , Swint S. A.
Published: April 2003

Silicone polyimides were made with siloxane‐equilibrated 1,3‐bis (3,4‐dicarboxyphenyl) ‐ 1,1,3,3‐tetramethyldisiloxane dianhydride (PADS) as the soft portion and [(1‐methylethylidene) bis (4,1‐phenyleneoxy)] bis‐1,3‐isobenzofurandione (BPADA) as the hard portion in combination with either para or meta‐phenylene diamine. The silicone polyimides were made with varying siloxane chain lengths and with varying overall weight percent silicone. There were linear correlations between these variables and flexural modulus, percent elongation at break, and cut‐through temperature. Glass transition temperatures were evaluated by dynamic mechanical analysis and the thermal stabilities were determined to be greater than 400°C by thermal gravimetric analysis. Melt viscosities were determined on the various copolymers and demonstrated a correlation between type of amine used, siloxane chain length, and overall weight percent silicone.
Catalytic chain transfer in polymerization of methyl methacrylate. II. Continuous synthesis and purification of macromer
Authors: Suddaby K. G. , Sanayei R. Amin , Rudin A. , O'driscoll K. F.
Published: April 2003

A continuous process for the production of kilogram quantities of poly(methyl methacrylate) macromers using catalytic chain transfer agents is described. The macromers are synthesized in a tubular reactor and isolated from unreacted monomer using a twin‐screw extruder. Three concentrations of catalytic chain transfer agent were used and macromers of Mn = 480, 752, and 1334 were made. The behavior of the tubular reactor runs over time was determined by monitoring both conversion and the molecular weight distribution of the macromers in the reactor effluent. Trends in this behavior with respect to time and catalytic chain transfer agent concentration are discussed. Experimental details are given and the efficiency of the devolatilization of the monomer from the reactor effluent using a twinscrew extruder is examined.
Synthesis and characterization of poly(methyl methacrylate‐co‐2‐hydroxypropyl methacrylate)‐graft‐polyoxyethylene
Authors: Jialanella Gary L. , Piirma Irja
Published: April 2003

This study involved the synthesis and characterization of an amphipathic graft copolymer, poly(methyl methacrylate‐co‐2‐hydroxypropyl methacrylate)‐graft‐polyoxyethylene. This amphipathic graft copolymer was synthesized utilizing a “grafting‐onto” technique in which α‐hydroxy‐ω‐methoxypolyoxyethylene was reacted with prepolymerized poly(methyl methacrylate‐co‐glycidyl methacrylate). Proof of copolymer formation was illustrated using water solubility, GPC, FTIR spectroscopy, and 13C‐NMR spectroscopy. In all cases, proof of copolymer formation is demonstrated unequivocally.
Phenyl acrylates and divinyl benzene cross‐linked copolymers as basic novel supports: Synthesis and characterization
Authors: Narasimhaswamy T. , Reddy B. S. R.
Published: April 2003

Suspension Copolymerization of glycidyl methacrylate (GMA), phenyl methacrylate (PhMA), 2,4,6‐tribromophenyl acrylate (TBPA), and 4‐acetylphenyl acrylate (APA) with divinyl benzene (DVB) was carried out at 80 ± 1°C in aqueous medium, as basic supports for possible applications in polymer‐supported chemistry. The resulting copolymer heads were characterized with various techniques. The identification of monomers in the copolymer was attempted using FTIR and 13C‐CP/MAS‐NMR spectroscopic techniques. The optical and scanning electron microscopic methods were used to study the shape, size, and surface morphology of the beaded copolymers. The particle‐size distribution was measured, and the average particle size of the particulate copolymers were carried out using a Malvern particle‐size analyzer. The decomposition temperatures and energy of activation involved in the thermal degradation were studied with thermogravimetry. The solvent imbibition of the polymer supports in various solvents was carried out with a centrifuge method.
Synthesis and evaluation of hexafluorodimethylcarbinol functionalized polymers as microsensor coatings
Authors: Snow A. W. , Sprague L. G. , Soulen R. L. , Grate J. W. , Wohltjen H.
Published: April 2003

Polystyrenes, polyacrylates, and poly(3,4‐isoprenes) incorporating the hexafluorodimethylcarbinol functionality have been synthesized, characterized, and tested as microsensor coatings on a surface acoustic wave (SAW) device for dimethyl methylphosphonate (DMMP) vapor absorption sensitivity. The syntheses involved monomer functionalization and polymerization or hexafluoroacetone reaction with preformed polymer. All fluoroalcohol functionalized polymer coatings displayed sub parts per million level sensitivity with the slope of the absorption isotherm steepest at low DMMP concentrations. The order of sensitivity for the isomeric polystyrene fluoroalcohols (meta > para ≫ ortho) paralleled that of the relative free hydroxyl to hydrogen‐bonded hydroxyl content. Strong hydrogen bonding between the fluoroalcohol polymers and DMMP vapor was observed by IR spectroscopy. Acylation of the fluoroalcohol group markedly reduced the DMMP sensitivity.
Textures of ethyl cellulose–dichloroacetic acid mesomorphic solution
Authors: Huang Y. , Zhou J. Y.
Published: April 2003

Textures of the ethyl cellulose (EC)‐dichloroacetic acid (DCA) mesomorphic solution were studied systematically by polarizing microscopy and small‐angle light scattering. It was found that with increasing polymer concentration, the mesophase could show a disklike texture, an oil streak texture, a pseudoisotropic texture, and an iridescent planar texture. Within the mesophase the ordering degree is different in different zones. The phase transition between anisotropic and isotropic phases could also be accomplished by changing temperature. With increasing temperature the mesophase with the lower degree of order could first transform to the isotropic phase and the phase transition from an anisotropic phase with a higher degree of order to the isotropic one could take place only at the higher temperature. A disklike texture was also observed during the phase transition between the anisotropic and isotropic phases when the solution was heated and it was probably a basic texture in polymer cholesteric liquid crystals.
Polyethylene–poly(methacrylic acid‐co‐divinylbenzene) interpolymer‐type carboxylic membranes
Authors: Wycisk Ryszard , Trochimczuk Witold M.
Published: April 2003

A short review of the methods of preparation of carboxylic membranes was presented. Details were given on the preparation procedure of polyethylene‐poly(methacrylic acid‐co‐divinylbenzene) PE‐poly(MA‐co‐DVB) interpolymer‐type carboxylic membranes and on the optimization of the procedure. The membranes were synthesized by swelling PE in sheet form in a mixture of MA, DVB, and benzoyl peroxide (BP), with subsequent heating of the gel to interpolymerize the monomers. The dependence of ion exchange capacity, swelling, resistivity, and permeability on poly(MA‐co‐DVB) and DVB contents were investigated. With the use of an electron microscope a domain‐type morphology was observed at low poly(MA‐co‐DVB) and DVB contents. Crystallinity of PE was not influenced by the presence of poly(MA‐co‐DVB).
Nylon 4/PVA blend membrane for dialysis
Authors: Lai J. Y. , Chen Y. C. , Hsu K. Y.
Published: April 2003

To improve the hydrophilicity and enhance the transport flux of nylon 4 membrane for dialysis, this study attempts to utilize blending nylon 4 with poly(vinyl alcohol) (PVA). The instability of PVA in water can be obtained more easily than by other methods, such as chemical, γ‐ray irradiated crosslinking, or high‐temperature treatment used by previous researchers. The effects of maturation time of the casting solution, nylon 4/PVA ratios, and casting solvent compositions on esterification of PVA, salt permeability, water content, partition coefficient, diffusivity, and mechanical strength of membrances are studied. The membrane, prepared by casting solution of nylon 4/PVA = 9/1 wt % formic acid with 24‐h maturation time, possesses permeabilities of NaCl and urea, 33.14 and 19.67 × 10−5 cm2/min, respectively.
Amines release from schiff bases polymers and diffusion from dosage forms with eudragit RL in acidic medium
Authors: Chafi Nafa , Kolli Malika , Vergnaud Jean‐Maurice , Montheard Jean‐Pierre
Published: April 2003

Chloromethylstyrene 1 (mixture meta and para; 60/40) can be oxydized in corresponding aldehyde 2. Vinylbenzaldehyde 2 reacts with primary amines such as aniline, benzylamine, 2‐phenylethylamine, 3‐phenylpropylamine, and 2‐aminopyridin to give Schiff bases that are polymerized in bulk with a radical initiator. Poly(vinyl benzaldehyde) 6 prepared from corresponding monomer 2 also reacts with primary amines to give polymeric Schiff bases. Hydrolyses of these polymeric imines have been carried out either in heterogeneous acidic medium or basic heterogeneous medium; a suitable percentage of amines has been released after some hours. Finally, a study of hydrolysis and of diffusion of released amines in a dosage form (Eudragit RL) has been also carried out with some polymeric Schiff bases.
Curing reaction and product properties of polysulfones terminated with active functional groups
Authors: Jin Shijiu , Yee Albert F.
Published: April 2003

The curing processes of maleimide‐terminated polyether sulfone oligomers (Mn from 1100 to 3000) and ethynyl‐terminated polysulfone prepolymers (Mn from 2600 to 12000) were investigated by means of DSC. The initial temperature of cure reaction is increased, and the apparent activation energy Ea of cure reaction is decreased as the Mn of the uncured prepolymer increases. On the basis of the Tg changes during the curing process, the kinetics of cure is proposed to be similar to a stepwise reaction, although the curing reaction is believed to proceed via a free radical chain mechanism. In this proposed reaction some initial reaction products with many branches and one remaining active functional group are formed first. The more these products occur, the more likely they can interreact to form a network. During the curing process the mobility of the active end group is restricted by the rigid polysulfone chain. Therefore, the reaction is mainly controlled by the movement of polymer, i.e., by the kinetics of diffusion. Films of these cured polymers were made by casting from solution. Their β relaxation peaks at low temperatures were examined by dielectric and dynamic mechanical measurements. The films made of the prepolymer with Mn > 3000 are flexible and foldable.
Syntheses and properties of polymers that undergo no shrinkage on cross‐linking by self‐catalyst
Authors: Tagoshi Hirotaka , Endo Takeshi
Published: April 2003

The polymers containing spiroorthoester and benzyl sulfonium salt moieties were prepared by the ternary radical polymerization of unsaturated spiroorthoester 2‐methylene‐1,4,6‐trioxaspiro [4.6] undecane (1) or 2‐methylene‐9‐methyl‐1,4,6‐trioxaspiro [4.5] decane (2) with vinyl benzyl sulfonium salt (VBS+SbF−6, 3) and vinyl monomers (acrylonitrile or methyl acrylate). The obtained ternary copolymers such as PI, PII, PIII, and PIV underwent curing over 75°C by self‐catalyst to obtain the corresponding gelled polymers, with expansion or only slight shrinkage on curing.
Dynamic mechanical analysis of tropical wood–polymer composites
Authors: Yap M. G. S. , Que Y. T. , Chia L. H. L.
Published: April 2003

Wood–polymer composites (WPC) of Geronggang (GE; Cratoxylon arborescens), a light tropical hardwood, impregnated with methyl methacrylate (MMA) and styrene‐co‐acrylonitrile (3 : 2; STAN), were prepared by in situ polymerization using γ radiation or catalystheat treatment. The dynamic flexural storage modulus, E′, for oven‐dried GE, moist GE, and GE–MMA and GE–STAN composites decreased with increasing temperature. The percentage decreases for GE with 10 and 16.5% moisture contents were 74.5 and 98.2%, respectively, which were higher than those for GE and GE composites, which ranged between 40 and 50%. The impregnated polymers were not as effective as water in acting as plasticizers, due to their nonpolar nature and much higher molecular weights. The α‐transition peaks for moist GE and GE composites were more distinct and were shifted to lower temperatures than those for oven‐dried GE. The values ranged between 75 and 150°C for moist GE and between 102 and 170°C for the GE composites. The α‐transitions of the catalyst–heat‐treated GE composites were lower than that of the radiation‐induced counterparts. GE–STAN composites were also observed to have lower α‐transition temperatures than those for GE–MMA for the respective treatment process, which seems to suggest that STAN interacted to a greater extent with cell wall components than did MMA.
Cross‐linking decrystallized and partially acetylated cotton yarn with dimethylol–dihydroxy–ethylene–urea
Authors: Varadarajan P. V. , Nachane Nayana D. , Sitaram M. S. , Patil N. B.
Published: April 2003

Easy‐care finishing of cotton fabrics invariably results in the loss of mechanical properties of the fabrics. There have been many attempts from time to time by different workers to reduce the above loss in the mechanical properties. But the problem is yet to be resolved satisfactory. As the uniform distribution of cross‐links in the resin‐finished structure of cellulose is the key for achieving a better balance of mechanical properties, the present work aims at a suitable modification of the cellulose matrix to achieve the goal. The paper reports the mechanical properties of the modified and cross‐linked cotton yarn. The cross‐linked samples of the modification treatment involving swelling the yarn at normal stretch with 20% NaOH and partially acetylating without washing off the alkali have displayed higher tenacity, elongation, and toughness, with better easy‐care properties as compared to the control.
Thermal properties of tropical wood–polymer composites
Authors: Yap M. G. S. , Que Y. T. , Chia L. H. L. , Chan H. S. O.
Published: April 2003

Wood–polymer composites (WPC) of Geronggang (GE; Cratoxylon arborescens), a light tropical hardwood, impregnated with methyl methacrylate (MMA), styrene‐co‐acrylonitrile (3: 2; STAN), methyl methacrylate‐co‐bis (2‐chloroethyl) vinyl phosphonate (3 : 1; MVP) and methyl methacrylate‐co‐bis (chloropropyl)‐2‐propene phosphonate (3:1;MPP), were prepared by in situ polymerization using γ‐radiation or catalyst‐heat treatment. Thermal characterization of these WPC by limiting oxygen index measurements (LOI), thermogravimetry (TG), and differential scanning calorimetry (DSC) showed that the impregnants greatly modified the wood properties. The LOI values of the GE–MVP and GE–MPP composites were much higher than that for GE and the other composites, indicating the effectiveness of the phosphonates as flame retardants. Concomitantly, the flaming characteristics also compared favorably against that for GE and the other composites. The decomposition temperature and maximum rate of weight loss determined by TG for GE–MVP and GE–MPP were substantially reduced, whereas the char yields were greatly higher. These observations again indicate that phosphonates imparted flame‐retarding properties to their composites. The thermal properties of GE–MMA and GE–STAN composites were not vastly different from that of untreated GE. Flame retardancy in the phosphonate‐containing composites was effected through both the condensed‐ and gaseous‐phase mechanisms due to the presence of phosphorus and chlorine, respectively. Indication of grafting of polymer to wood was found for GE–STAN, GE–MVP, and GE–MPP composites, but not for GE–MMA. Composites prepared by γ‐radiation or by the catalyst‐heat treatment had similar thermal characteristics.
Polymers derived from 2‐furaldehyde and aromatic diamines. I
Authors: Patel Hasmukh S. , Majmudar Gopal H.
Published: April 2003

Poly[imino (cyclopent‐2‐en‐1‐one‐2,4‐diyl) iminoarylenes] were prepared by the condensation of 2‐furaldehyde with various aromatic diamines in solution at room temperature. All polycondensations were carried out in one step and under identical conditions. It was observed that the most likely condensation reaction is through the furan rearrangement that leads to poly[imino (cyclopent‐2‐en‐1‐one‐2,4‐diyl) iminoarylenes]. The structures of all the polymer samples were confirmed by elemental analyses and by comparison of IR spectral characteristics with those of a model compound derived from 2‐furaldehyde and aniline. Number average molecular weights of all polymer samples were estimated from nonaqueous conductometric titration. The viscometric measurements of solutions of polymer samples in a formic acid–acetic acid (85 : 15) (v/v) mixture exhibited polyelectrolyte behavior. The thermal properties of polymer samples were revealed by thermogravimetry. The formation of the polymeric product is also explained. The result of preliminary tests for glass reinforcement of commercial epoxy resin and produced polymer samples suggest that laminate sheets with good mechanical strength can be obtained.
ESR studies of solvent penetration into polymer‐blend‐like material: Particles formed from poly(methyl methacrylate) and polyisobutylene
Authors: Pekcan Önder , Demir Yusuf
Published: April 2003

Solvent penetration into nonaqueous dispersions (NAD) of poly(methyl methacrylate) (PMMA) sterically stabilized by PIB were studied by ESR spectroscopy. These colloidal particles were exposed to dilute solution of spin probe 3‐carbomoyl 2,2,5,5‐tetramethyl 3‐pyrolin‐1‐yloxy and the bimodal distribution of ESR spectra of this probe molecules were carefully monitored as a function of time. Fickian type diffusion of spin probes into the particles was observed and a spherical model was employed to obtain the diffusion coefficients (D) in various solvents. D values were found around 10−15 cm2/s, and interpreted as the parameter, inversely proportional to the apparent viscosity of the environment inside the colloid particle. Maximum amount of diffused solvent molecules (M∞) into the PMMA particle was found inversely proportional to polymer‐solvent interaction through the solubility parameters. The interconnected network of PIB was found to be responsible for the penetration of spin‐probe (i.e., solvent) molecules into the glassy PMMA phase and/or PIB‐PMMA interface.
Linear polyesters. Products of interfacial polycondensation of bis(4‐hydroxyphenyl) ether with isomeric phthaloyl chlorides
Authors: Podkoscielny Wawrzyniec , Wdowicka Danuta
Published: April 2003

New polyesters were obtained by interfacial polycondensation of bis(4‐hydroxyphenyl) ether with phthaloyl, isophthaloyl, and terephthaloyl chlorides. The initial reaction conditions were as follows: the aqueous to organic phase ratio 1 : 1, reaction temperature 25°C, the rate of chloride addition about 10 min, and molar ratio of the reagents diol/acid dichloride 1 : 1.1, benzene‐hexane as an organic phase. To determine the optimal conditions for interfacial polycondensation, the influence of the following factors on yield and value of reduced viscosity were studied: organic phase, excess of sodium hydroxide as an acceptor of HCl, contribution of benzyltriethylammonium chloride as a catalyst, and contribution of an emulsifier, Mersolan. The structure of all polyesters was determined by elemental analysis and infrared spectra. Initial decomposition and initial intensive decomposition temperature were defined by the curves of thermogravimetric analysis. Some mechanical and electrical properties of isophthaloyl polyester, only partly soluble in organic solvents, were determined.
Immobilization of catalase by polyion complex
Authors: Kohjiya Shinzo , Maeda Kazuyuki , Yamashita Shinzo
Published: April 2003

Catalase was immobilized in a polyion complex from poly(sodium 2‐acrylamide‐2‐methyl‐1‐propanesulfonate) and poly[2‐(trimethylammonioethyl) methacrylate chloride]. Polyion complex formation between the two polyions was found to proceed stoichiometrically by the turbidimetric titration. Immobilization of catalase was achieved by conducting the complexation in the presence of the enzyme, which was established to be incorporated in the polyion complex networks. The fixed catalase showed higher thermal stability than the original enzyme. Furthermore, the stability and the activity of the fixed catalase were improved by annexing inert components such as albumin, histone, or lecithin at the time of polyion complex formation.
Determination of cohesive energy density of polyacrylamide by swelling measurements
Authors: Bajpai U. D. N. , Bajpai A. K.
Published: April 2003

Polyacrylamide was prepared by a suitable redox system in oxygen atmosphere and its cohesive energy density (ced) was determined from swelling measurements. The molecular weight of polymer was also determined by viscosity measurements.