Polymer resin polyvinylacetal

The most stable resin for many of our purposes has proven to be a copolymer of ethyl methacrylate and methyl acrylate. This comes as little surprise the Rohm and Haas Company has for years sold a durable resin based on these two monomers, Acryloid B-72 (6,28). We have also prepared polymers of similar physical properties based on methyl methacrylate and ethyl acrylate and have found that their behavior is practically the same - the methyl and ethyl groups apparently do not become seriously involved in crosslinking. As reported elsewhere( 23), rather than crosslink, Acryloid B-72 tends to chain break under visible and near-ultraviolet radiation, although at a very slow rate. Polyvinylacetate is another polymer used in the care of museum objects that tends more to chain break than crosslink under these conditions(23), but it is not our purpose to discuss its properties at this time. 

The surface energy of fibres is closely related to the hydrophility of the fibre. Some investigations are concerned with methods to decrease hydrophility. The modification of wood-cellulose fibres with stearic acid [49] causes those fibres to become hydrophobic and improves their dispersion in PR As can be observed in jute reinforced unsaturated polyester resin composites, treatment with polyvinylacetate increases the mechanical properties [50] and moisture repellence. Silane coupling agents may contribute hydrophilic properties to the interface, especially when amino-functional silanes, such as epoxies and urethane silane are used as primers for reactive polymers. The primer may supply much more amine functionality than can possibly react with the resin at the interphase. Those amines, which could not react, are hydrophilic and therefore responsible for the poor water resistance of the bonds. An effective way to use hydrophilic silanes is to blend them with hydrophobic silanes such as phenyltrimethoxysilane. Mixed siloxane primers also have an improved thermal stability, which is typical for aromatic silicones [48]. 

MAJOR POLYMER APPLICATIONS ABS, acrylics, cellulose acetate, epoxy resin, ethylene propylene diene copolymer, ethylene vinyl acetate copolymer, polyamide, polycarbonate, polyester, polymethylmethacrylate, polypropylene, polystyrene, polysulfone, polyurethane, polyvinylacetate, polyvinylchloride, proteins, rubber, SB starch ... 

Strength properties with impervious substrates as well as with wood. They are combined with thermoplastic polymers to provide both metal-to-metal or metal-to-paper or plastic bonding. It is postulated that the phenolic crosslinks to rubber through quinone methide intermediates by a 1-4 addition across the vinyl double bonds. Some of the main materials are NBR with 15-40% acrylonitrile in nitrile/phenolic resins and polyvinylacetal in vinyl/phenolic blends. In all cases the phenolic gives inherent strength, solvent resistance, and thermal stability to the adhesive. 

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