Poly copolymers, thermal stabilizers

Poly(hydroxyphenyl maleimide)-b-PBA was added to thermosetting phenol resin to improve heat resistance [63]. PVC blended with poly(vinyl copolymer having cyclohexyl maleimide group)-b-PVC showed improved heat resistance and tensile strength with thermal stability during processing [64]. 

Poly(ether ester) (PEE) copolymers were consisted of soft segments of polyethers and hard crystalline segments of polyesters. Depending on the polyether/polyester ratio, PEE copolymers exhibit a wide range of mechanical behavior combined with solvent resistance, thermal stability, and ease of melt process ability. 

Thus, we have chosen the alternating copolymer of DMBZMA with MST as our resist material for its high thermal stability (Tg=210°C). TGA curves of the DMBZMA-MST copolymers are compared with that of PDMBZMA in Figure 5. Although incorporation of MST does not affect the deprotection temperature, the copolymers exhibit lower main chain stability than PMAN (PDMBZMA becomes PMAN above 260°C) and behave like PMMA and poly(a-methylstyrene) in terms of their main chain stability. 

For example, by using 90 parts of vinyl chloride and 10 parts of vinyl acetate, the random copolymer formed has the toughness of poly (vinyl chloride), thermal stability of poly (vinyl acetate) and solubility akin to poly (vinyl acetate). These combination of properties makes it useful as a paint. 

ISO 305, Plastics - Determination of thermal stability of poly(vinyl chloride), related chlorine-containing homopolymers and copolymers and their compounds - Discoloration method, 1990. 

Polymer Solvent. Sulfolane is a solvent for a variety of polymers, including polyacrylonitrile (PAN), poly(vinylidene cyanide), poly(vinyl chloride) (PVC), poly(vinyl fluoride), and polysulfones (124—129). Sulfolane solutions of PAN, poly(vinylidene cyanide), and PVC have been patented for fiber-spinning processes, in which the relatively low solution viscosity, good thermal stability, and comparatively low solvent toxicity of sulfolane are advantageous. Powdered perfluorocarbon copolymers bearing sulfo or carboxy groups have been prepared by precipitation from sulfolane solution with toluene at temperatures below 300°C. Particle sizes of 0.5—100 Jim result. 

Phthalocyanine Polymers. Phthalocyanin-imide polymers show an initial decomposition temperature > 500 °C both in air and inert atmosphere (Co, Ni, Cu, Zn) as expected. An increase in the concentration of metal phthalocyanine in the copolymer increases the thermal stability [70]. Poly(Cu 2,3,9,10,16,17,23,24-octacyanophthalocyanine) represents an unique polymer showing enhanced thermal stability (1.2% wt loss at 585 °C and 1.5% wt loss at 625 °C, 21.6% at 800 °C) in He atmosphere Rapid oxidation takes place on heating above 560 °C (9% wt loss at 585 °Q [99] in air. The enhanced stability of this material is different from that of monomeric metal phthalocyanine compounds which sublime and loose most of their weight around 600 °C [99]. 

Copolymerization. Vinyl chloride can be copolymerized with a variety of monomers. Vinyl acetate, the most important commercial comonomer, is used to reduce crystallinity, winch aids fusion and allows lower processing temperatures. Copolymers are used in flooring and coatings. This copolymer sometimes contains maleic add or vinyl alcohol (hydrolyzed from the poly(vinyl acetate ) to improve the coating s adhesion to other materials, including metals, Copolymers with vinylidene chloride are used as barrier films and coatings. Copolymers of vinyl chlonde with acrylic esters in latex from are used as film formers in paint, nonwoven fabric binders, adhesives, and coatings. Copolymers with olefins improve thermal stability and melt flow, but at some loss of heat-deflection temperature,... 

This hypothesis has been confirmed by the greatly improved thermal stability of PVC as a result of the formation of a graft copolymer of d -l,4-polybutadiene onto poly (vinyl chloride). The improved thermal stability is demonstrated by the almost total absence of discoloration on molding the graft copolymer into a film at 200°C in air, the reduced rate of dehydrochlorination on heating in an inert atmosphere at 180°C, and higher onset and peak temperatures for hydrogen chloride evolution as determined by differential thermal analysis. 

Thermal analysis (TGA) data of these siliconated block copolymers revealed that they are thermally more stable than the reference materials, poly(tetrahydrofuran block urethane) and poly(ethyleneglycol block urethane) copolymers. The thermal stability was found to depend on the silicone content, with stability increasing as the silicone content in the structure increases. 

For polyester, the reported work82 done in Sichuan University of China, involves adding MMT clay in a copolymer of poly(ethyleneterephthalate), which with a phosphorus-containing monomer could produce PET with higher thermal stability and char-forming tendency. However, fibers were not produced from this PET-nanocomposite polymers. 

For much of the last century, scientists attempted to make useful plastics from hydroxy adds such as glycolic and lactic acids. Poly(glycolic acid) was first prepared in 1954, but was not commercially developed because of its poor thermal stability and ease of hydrolysis. It did not seem like a useful polymer. Approximately 20 years later it found use in medicine as the first synthetic suture material, useful because of its tendency to undergo hydrolysis. After the suture has served its function, the polymer biodegrades and the products are assimilated (Li and Vert 1995). Since then, suture materials, prosthetics, artificial skin, dental implants, and other surgical devices made from polymers and copolymers of hydroxy carboxylic acids have been commercialized (Edlund and Albertsson 2002). 

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