Vinyl acetate-methacrylate copolymer

Dental Polymers. Every year nearly a half billion dental fillings are done, and over a million dentures are constructed. Most of the materials used in each of these cases are polymeric. In addition, over 300,000 dental implants are made each year with either ceramics or polymers (1). The majority of the dental fillings and dentures are made from various copolymers of methyl methacrylate with other acrylics, although some other polymers, such as polyurethanes, vinyl chloride-vinyl acetate-methacrylate copolymers, vulcanized rubber, and epoxies, have been used to some extent. One major problem is aesthetics—the prosthesis must look natural and not discolor (by photoinduction or staining) to any great extent. 

NR, styrene-butadiene mbber (SBR), polybutadiene rubber, nitrile mbber, acrylic copolymer, ethylene-vinyl acetate (EVA) copolymer, and A-B-A type block copolymer with conjugated dienes have been used to prepare pressure-sensitive adhesives by EB radiation [116-126]. It is not necessary to heat up the sample to join the elastomeric joints. This has only been possible due to cross-linking procedure by EB irradiation [127]. Polyfunctional acrylates, tackifier resin, and other additives have also been used to improve adhesive properties. Sasaki et al. [128] have studied the EB radiation-curable pressure-sensitive adhesives from dimer acid-based polyester urethane diacrylate with various methacrylate monomers. Acrylamide has been polymerized in the intercalation space of montmorillonite using an EB. The polymerization condition has been studied using a statistical method. The product shows a good water adsorption and retention capacity [129]. 

Adhesion of Coatings. Except for K-l polycarbonate [4,4 -(2-nor-bornylidene)diphenol polycarbonate] (4), an experimental polymer (inherent viscosity 0.85), all the coatings were prepared with commercial products EAB-381-0.5 and EAB-381-20 cellulose acetate butyrates from Eastman Chemical Products, Inc. VYHH vinyl chloride (87%)/vinyl acetate (13%) copolymer from Union Carbide Corp. Butvar B76 poly-(vinyl butyral) from Shawinigan Resins Corp. Plexiglas V poly (methyl methacrylate) from Rohm and Haas Co. Dylene P3I polystyrene from... 

Ethylene-vinyl acetate-methacrylic acid copolymer... 

The two pottant materials studied in this report are plasticized polyvinyl butyral (plPVB) which is easily available and used in safety glass, and a highly stabilized, peroxide crosslinked ethylene/vinyl acetate (EVA) copolymer containing about 33 weight % vinyl acetate (.7). The outer cover/insulator materials studied include polyvinyl fluoride (PVF) and a butyl aerylate/methyl methacrylate graft copolymer (BAgMMA) both are blown films. 

Styrene-butadiene rubber latex (SBR, GRS) and acrylonitrile-butadiene rubber latex (NBR) are two of the earliest to arrive on the market. Since then, many other types have appeared, with poly(vinyl acetate) and copolymers, acrylics (generally polymers and copolymers of the esters of acrylic acid and methacrylic acids), and carboxylic-SBR types being the major products. Since latices are aqueous emulsions, less... 

Vinyl acetate is relatively inexpensive and is readily copolymerized with vinyl chloride, ethylene, acrylates and methacrylates. The monomer is a colourless, flammable liquid with an initial pleasant odour, which on exposure becomes irritating. One of the major disadvantages of vinyl acetate-based copolymers is their poor hydrolytic and UV stability. This was shown to improve when copolymerized with vinyl esters of versatic acid [18]. Copolymers of vinyl acetate with the vinyl esters of versatic acid have been used in Europe for the last quarter-century. In the US similar monomers were introduced in the past five years, two of which are illustrated in Table 6.1, namely, vinyl pivalate and vinyl neo-decanoate. More details of the copolymerization of these monomers with vinyl acetate is given in Chapter 16. 

Photolabile groups on polymers can serve as sites for photoinitiated graft copolymerizations. For instance, when polymers and copolymers of vinyl ketone decompose in ultraviolet Imht in the presence of acrylonitrile, methyl methacrylate, or vinyl acetate, graft copolymers form ... 

It is necessary to be able to identify and quantify the additives in polymers and vibrational spectroscopy is a particularly useful approach to this problem. Compared with traditional chemical analyses, vibrational methods are nondestructive and are time-and cost-effective as well as more precise. A large number of examples exist in the literature. For example, antistatic agents (polyethylene glycol (PEG) in polyethylene (PE)) can be detected directly using FTIR sampling (367). An IR spectroscopic technique for the analysis of stabilisers (2, 6-di-tert-butyM-methylphenol) in PE and ethylene-vinyl acetate (EVA) copolymer has been described (368). It is possible to quantify the amount of external and internal lubricants (stearic acid in polystyrene (PS)) (371). Fillers in polymers can also be analysed (white rice husk ash (predominantly silica in polypropylene (PP)) (268). Raman spectroscopy has been used to detect residual monomer in solid polymethyl methacrylate (PMMA) samples (326). 

Poly(vinyl acetate) (PVAc) and vinyl acetate (VAc) copolymer coatings in latex form for buildings possess good light resistance, a medium stability to chemicals and low cost. VAc-methacrylate copolymers form good paints for interior and exterior application [54, 93]. 

Thermoplastics used to blend with NR include PS, " polyamide 6, ethylene-vinyl acetate (EVA) copolymer, poly(methyl methacrylate) (PMMA), polypropylene (PP), low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE) " and high-density polyethylene (HDPE). To improve the properties of TPNR, modified NR is also used. ENR is the most frequently used modified NR. TPNR blends are prepared by blending NR and thermoplastics in various proportions. The role of rubber is to improve the impact strength and ductility of the plastic. Depending on the ratio, materials with a wide range of properties are obtained. The stiffness of the rubber is increased with the incorporation of plastic into the rubber matrix. The mechanical properties of TPNR again depend on the proportions of the rubber and thermoplastic components. The elastic properties of TPNR are considerably... 

Other Olefin Copolymers and Terpolymers Ethylene-ethyl acrylate UCC, Dow Chemical, DuPont Ethylene-acrylic acid Dow Chemical Ethylene-methacrylic acid DuPont Ethylene-vinyl acetate-methacrylic acid DuPont... 

Vinyl acetate/methacrylic acid copolymer tetrahydrofuran LLE 174... 

Applications of the technique have been discussed in various fields. Willis and Wheeler demonstrated the determination of the vinyl acetate (VA) distribution in ethylene-vinyl acetate (EVA) copolymers, the analysis of branching in high-density polyethylene (PE), and the analysis of the chemical composition of a jet oil lubricant. Provder et showed that in powder coatings all additives were positively identified by SEC-FTIR through comparison of the known spectra. Even biocides could be analyzed in commercial house paints. The comparison of a PS-PMMA blend with a corresponding copolymer gave information on the chemical drift. The analysis of a competitive modified vinyl polymer sample by SEC-FTIR showed that some of the components of the binder could be identified readily as vinyl chloride, ethyl methacrylate, and acrylonitrile, and an epoxidized drying oil additive was detected. 

A number of methods such as ultrasonics (137), radiation (138), and chemical techniques (139—141), including the use of polymer radicals, polymer ions, and organometaUic initiators, have been used to prepare acrylonitrile block copolymers (142). Block comonomers include styrene, methyl acrylate, methyl methacrylate, vinyl chloride, vinyl acetate, 4-vinylpyridine, acryUc acid, and -butyl isocyanate. 

Other Polymers. Besides polycarbonates, poly(methyl methacrylate)s, cycfic polyolefins, and uv-curable cross-linked polymers, a host of other polymers have been examined for their suitabiUty as substrate materials for optical data storage, preferably compact disks, in the last years. These polymers have not gained commercial importance polystyrene (PS), poly(vinyl chloride) (PVC), cellulose acetobutyrate (CAB), bis(diallylpolycarbonate) (BDPC), poly(ethylene terephthalate) (PET), styrene—acrylonitrile copolymers (SAN), poly(vinyl acetate) (PVAC), and for substrates with high resistance to heat softening, polysulfones (PSU) and polyimides (PI). 

Many synthetic latices exist (7,8) (see Elastomers, synthetic). They contain butadiene and styrene copolymers (elastomeric), styrene—butadiene copolymers (resinous), butadiene and acrylonitrile copolymers, butadiene with styrene and acrylonitrile, chloroprene copolymers, methacrylate and acrylate ester copolymers, vinyl acetate copolymers, vinyl and vinyUdene chloride copolymers, ethylene copolymers, fluorinated copolymers, acrylamide copolymers, styrene—acrolein copolymers, and pyrrole and pyrrole copolymers. Many of these latices also have carboxylated versions. 

An a priori method for choosing a surfactant was attempted by several researchers (50) using the hydroph i1 e—1 ip oph i1 e balance or HLB system (51). In the HLB system a surfactant soluble in oil has a value of 1 and a surfactant soluble in water has a value of 20. Optimum HLB values have been reported for latices made from styrene, vinyl acetate, methyl methacrylate, ethyl acrylate, acrylonitrile, and their copolymers and range from 11 to 18. The HLB system has been criticized as being imprecise (52). 

Organic peroxides are used in the polymer industry as thermal sources of free radicals. They are used primarily to initiate the polymerisation and copolymerisation of vinyl and diene monomers, eg, ethylene, vinyl chloride, styrene, acryUc acid and esters, methacrylic acid and esters, vinyl acetate, acrylonitrile, and butadiene (see Initiators). They ate also used to cute or cross-link resins, eg, unsaturated polyester—styrene blends, thermoplastics such as polyethylene, elastomers such as ethylene—propylene copolymers and terpolymers and ethylene—vinyl acetate copolymer, and mbbets such as siUcone mbbet and styrene-butadiene mbbet. 

Diallyl terephthalate [1026-92-2] is utilized less, but lenses made of copolymers with triaHyl cyanurate and methacrylates have been suggested (62). Diallyl tetrabromophthalate and tetrachlorophthalate polymers have been proposed for electronic circuit boards of low flammabiUty (63). They are uv-curable and solder-resistant. Copolymers with unsaturated polyester, vinyl acetate and DAP have been studied (64). 

Small amounts of TAIC together with DAP have been used to cure unsaturated polyesters in glass-reinforced thermo sets (131). It has been used with polyfunctional methacrylate esters in anaerobic adhesives (132). TAIC and vinyl acetate are copolymerized in aqueous suspension, and vinyl alcohol copolymer gels are made from the products (133). Electron cure of poly(ethylene terephthalate) moldings containing TAIC improves heat resistance and transparency (134). 

Block copolymers of vinyl acetate with methyl methacrylate, acryflc acid, acrylonitrile, and vinyl pyrrohdinone have been prepared by copolymeriza tion in viscous conditions, with solvents that are poor solvents for the vinyl acetate macroradical (123). Similarly, the copolymeriza tion of vinyl acetate with methyl methacrylate is enhanced by the solvents acetonitrile and acetone and is decreased by propanol (124). Copolymers of vinyl acetate containing cycHc functional groups in the polymer chain have been prepared by copolymeriza tion of vinyl acetate with A/,A/-diaIlylcyanamide and W,W-diaIl5lamine (125,126). 

Poly(ethyl methacrylate) (PEMA) yields truly compatible blends with poly(vinyl acetate) up to 20% PEMA concentration (133). Synergistic improvement in material properties was observed. Poly(ethylene oxide) forms compatible homogeneous blends with poly(vinyl acetate) (134). The T of the blends and the crystaUizabiUty of the PEO depend on the composition. The miscibility window of poly(vinyl acetate) and its copolymers with alkyl acrylates can be broadened through the incorporation of acryUc acid as a third component (135). A description of compatible and incompatible blends of poly(vinyl acetate) and other copolymers has been compiled (136). Blends of poly(vinyl acetate) copolymers with urethanes can provide improved heat resistance to the product providing reduced creep rates in adhesives used for vinyl laminating (137). 

Because the polymer degrades before melting, polyacrylonitrile is commonly formed into fibers via a wet spinning process. The precursor is actually a copolymer of acrylonitrile and other monomer(s) which are added to control the oxidation rate and lower the glass transition temperature of the material. Common copolymers include vinyl acetate, methyl acrylate, methyl methacrylate, acrylic acid, itaconic acid, and methacrylic acid [1,2]. 

The molecules join together to form a long chain-like molecule which may contain many thousands of ethylene units. Such a molecule is referred to as a polymer, in this case polyethylene, whilst in this context ethylene is referred to as a monomer. Styrene, propylene, vinyl chloride, vinyl acetate and methyl methacrylate are other examples of monomers which can polymerise in this way. Sometimes two monomers may be reacted together so that residues of both are to be found in the same chain. Such materials are known as copolymers and are exemplified by ethylene-vinyl acetate copolymers and styrene-acrylonitrile copolymers. 

Polyvinyl alcohol is a main ingredient in latex paints, hairsprays, shampoos, and glues. It forms polymers and copolymers with other monomers, such as vinyl acetate and methyl methacrylate... 

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