Showing papers in "Polymer Degradation and Stability in 1998"

TL;DR: In this paper, the authors discuss the various technologies being used to produce polylactic acids and how monomer stereochemistry can be controlled to impart targeted utility in the final polymers.

TL;DR: New applications were described as thickener to maintain viscosity in food, cosmetics, etc., as nonwoven fabric or paper for old document repair, as food additives and others, and as a temporary substitute for human skin in the case of burns, ulcers, decubitus and others.

TL;DR: A new grade of BIONOLLE (coded #1900 series), which has a long chain branch (LCB), high melt tension and high recrystallization rate, has been developed, to enable stretched blown bottles and highly expanded foams to be made easily as mentioned in this paper.

TL;DR: Xanthan gum is a natural high molecular weight polysaccharide produced by a fermentation process and is a very effective stabilizer for water-based systems as mentioned in this paper, which is also used in cleaners, coatings, polishes and in agricultural flowables.

TL;DR: Organosoluble derivatives of chitin were prepared and used as precursors for regioselective and quantitative chemical modifications, and the effects of substituents were discussed.

TL;DR: In this article, poly(e-caprolactone) (PCL) was reactively blended with poly(lactic acid) (PLA) using three catalysts/coupling agents in a Haake twin screw mixing chamber.

TL;DR: In this article, the main results obtained by Novamont in the field of thermoplastics and complexed starch in the presence of specific synthetic polymers, and aspects, such as processability, physicochemical and physico-mechanical properties, composting behavior and future market perspectives of Mater-Bi products.

TL;DR: Very high levels of bacterial cellulose have been attained through strain selection, mutation, medium composition optimization and physico-chemical fermentation parameter control, and combining these nutritional, genetic and bioprocess-technological improvements.

TL;DR: By embedding natural fibres eg flax, hemp, ramie, etc into a biopolymeric matrix made of derivatives from cellulose, starch, lactic acid, etc, new fibre reinforced materials, the so-called biocomposites, were created at the DLR Institute of Structural Mechanics in 1989 and are still being developed as discussed by the authors.

TL;DR: The structure and function of synthetic polymeric materials can be damaged by biofilms in various ways, among these: (1) by coating the surface, masking surface properties and contaminating adjacent media such as water by released microorganisms; (2) by increasing the leaching of additives and monomers out of the polymer matrix by microbial degradation; (3) by attack by enzymes or radicals of biological origin to polymer and additives; leading to both embrittlement and loss of mechanical stability; (4) by accumulating water and penetrating the polymeric matrix with microbial filaments

TL;DR: Alginates may become useful in applications where reproducible and specific physical properties are required and be used to modify alginates in vitro to obtain polysaccharides with the desired content and distribution pattern of G.

TL;DR: The use of polylactide and its copolymers in the medical industry requires a high purity of all compounds and advanced quality systems as discussed by the authors, such as cGMP and Drug or Device Master Files.

TL;DR: In this article, a lot of jobs and a potential market of > 1 million tonnes/year for biodegradable plastics in Europe is proposed by the EU Commission Directorate General XII.

TL;DR: In this article, eight types of aliphatic polyesters were prepared by both biosynthetic and chemosynthetic methods, and their biodegradation tests were carried out at 25 °C for 28 days under aerobic conditions in different environmental natural waters.

TL;DR: In this article, different types of starch were processed in blend systems with natural plasticizers and commercial fibres by conventional extrusion and injection molding techniques, and it was shown that adding small amounts of fibres to the starch samples resulted in an increase of tensile strength and water resistance of these products.

TL;DR: In this paper, the effect of the presence of hydrido-substituents and/or vinyl end-groups on the thermal and thermo-oxidative stability of polysiloxanes was determined.

TL;DR: In this article, chemical and molecular weight changes were measured using FTIR and the latter was determined by size exclusion chromatography for polypropylene degradation, during multiple extrusion cycles at different temperatures.

TL;DR: In this article, a series of polyethylene/plasticized starch blends were prepared using a poly(ethylene-g-maleic anhydride) copolymer as a reactive compatibilizer.

TL;DR: In this article, the reaction of chitosan with aromatic aldehydes gave Schiff base polymers, which were characterized and identified using microanalysis and IR spectroscopy.

TL;DR: The ability of fungi and Streptomyces species to attack degradable plastics was investigated in pure shake-flask culture studies as discussed by the authors, where eight different isolated strains and two fungi Mucor rouxii NRRL 1835 and Aspergillus flavus were used.

TL;DR: In this article, a new mix of properties considering biodegradability, thermoplastic behavior and material properties as well as possible synthetic strategies and their realisation are presented, which can be used for cellulose-based materials.

TL;DR: In this paper, the influence of lignin content on the film mechanical properties was evaluated by stress-strain tests run at two ambient relative humidity levels, and the results were consistent with the hypothesis of a two-phase material consisting of a hydrophilic starch matrix filled with hydrophobic lignins aggregates, as confirmed by microscopic observations.

TL;DR: The monofilament suture fabricated from the l -lactide-ɛ-caprolactone (75/25) copolymer [P(LA/CL] elicited a very mild foreign-body reaction similar to PDS II®, in contrast with a silk suture.

TL;DR: In this paper, the thermal degradation of a commercial, stabilized, unfilled nitrile (Buna-N) rubber material was investigated at temperatures in the range 85-140 °C.

TL;DR: In this article, production wastes of different polytetrafluoroethylene (PTFE) compounds (containing carbon black, glass fibers and bronze) were pyrolysed in a fluidized-bed reactor to gain fluorocarbons.

TL;DR: The surface modifications of polyvinylidene fluoride (PVDF) induced by rf Ar plasma treatment have been investigated using X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM).

TL;DR: In this article, the authors present an overview of the current understanding of the complexities of filler-polymer and additive interactions with a major emphasis on carbon black, silica and titanium dioxide pigments.

TL;DR: In this paper, the structure, mechanical properties and susceptibility to degradation of blends of low density polyethylene (PE) or isotactic polypropylene (PP) and glycerol plasticized starch (GS) was investigated.

TL;DR: The combination of high technical performance and full biodegradability is significant for this new generation of thermoplastic materials as mentioned in this paper, and all of the above processes such as extrusion, film blowing, film casting, injection molding, blow molding and fiber spinning open a wide field of applications.

TL;DR: In this paper, conditions of the living homopolymerization of e-caprolactone (CL), lactides (LA), and of the homo-oligomerization of γ-butyrolacton (BL) are briefly described.