Ethylene vinyl acetate chemical structure

According to the chemical structure of the hot-melt adhesive polymers (polyamide resins, saturated polyester, ethylene vinyl acetate copolymers, polyurethanes), the processing temperatures range between 120 and 240 °C. 

Fig. 1. Chemical structures of barrier polymers, (a) Vinylidene chloride copolymers (b) hydrolyzed ethylene—vinyl acetate (EVOH) (c) acrylonitrile barrier polymers (d) nylon-6 (e) nylon-6,6 (f) amorphous nylon (Selar PA 3426), y = x + 2 (g) nylon-MXD6 (h) poly(ethylene terephthalate) and (i) poly(vinyl...

Ethylene]vinyl acetate. Symbolized as E/VAC according to ISO 1043 but the abbreviation of EVA is extensively used in the literature. Copolymer of ethylene and vinyl acetate. Its flexibility is similar to that of the plasticized PVC but in this case it is an inherent property due to the chemical structure without any incorporation of a plasticizer. As a thermoplastic, it is processed by extrusion or injection moulding. Strainability of E/VAC films is higher than that of LDPE. Applications injection moulded shoe soles, bathing sandals, and other consumer goods impact modifier for rigid PVC. Trade names Levapren (FRG), Ultrathene (USA). 

The family of polyolefins includes polyethylene, polypropylene, ethylene-vinyl acetate, ionomers, polybutylene, polyisobutylene, and polymethylpentene. Because the chemical and electrical properties of the various polyolefins are basically similar, they often compete for the same applications. However, since the different strength and modulus properties vary greatly with the type and degree of crystallinity, as seen in the preceding tables and figures, the tensile, flexural, and impact strength of each polyolefin may be quite different. Their stress-crack resistance and useful temperature ranges may also vary with their crystalline structure. 

Early hot melt adhesives were based on ethyl cellulose and animal or hide glues. These were later replaced by synthetic resins such as polyamides and ethylene-vinyl acetate copolymers. More recently a new class of compounds, referred to as block copolymers because of their unique chemical structure, have emerged. These latter compounds are copolymers of styrene and butadiene, isoprene, or ethylene-butylene which tend to widen the flexibility property range of hot melt adhesives. They probably represent the fastest growing segment of the hot melt adhesives market at the present time. Their primary application is in hot melt pressure sensitive adhesives. Polymers based on other than polyolefin resins are discussed in other chapters in this handbook. 

Chemical structure of ethylene vinyl acetate (EVA) copolymers... 

Ethylene-vinyl acetate copol5miers were molded on different substrates. The quality and the chemical structure of mold surface determined properties of copolymer (see more in Section 5.1). Selection of suitable mold surface may produce materials with good release properties without need to use additives. 

ISO and DIN Codes for Data Block 1 Data block I of the individual item block contains the abbreviation of the chemical name of the material, e.g., PA 12 (see example). This abbreviation may be followed by analytical data with respect to the composition of the material an example is the content of vinyl acetate units in ethylene-vinyl acetate copolymers. Such chemical structure data may be composition, such as content of vinyl acetate (VAC) or acrylonitrile units (AN), configuration as measured by isotacticity ( isotaxy ) (IT), branching as revealed by density (D). 

Copolymers of ethylene vinylacetate are the most commonly utilized fuel wax crystal modifiers. Other compounds such as vinyl acetate-fumarate copolymers, styrene-ester copolymers, diester-alphaolefin copolymers, as well as alkyl carbamate compounds are effective wax crystal modifiers. These compounds differ in both chemical structure and in the extent of performance provided. See FIGURES 6-7 and 6-8. 

The case study on Vinyl Acetate Process, developed in Chapter 10, demonstrates the benefit of solving a process design and plantwide control problem based on the analysis of the reactor/separation/recycles structure. In particular, it is demonstrated that the dynamic behavior of the chemical reactor and the recycle policy depend on the mechanism of the catalytic process, as well as on the safety constraints. Because low per pass conversion of both ethylene and acetic acid is needed, the temperature profile in the chemical reactor becomes the most important means for manipulating the reaction rate and hence ensuring the plant flexibility. The inventory of reactants is adapted accordingly by fresh reactant make-up directly in recycles. 

Figure 5.1. Molecular structures of the chemical repeat units for common polymers. Shown are (a) polyethylene (PE), (b) poly(vinyl chloride) (PVC), (c) polytetrafluoroethylene (PTFE), (d) polypropylene (PP), (e) polyisobutylene (PIB), (f) polybutadiene (PBD), (g) c/5-polyisoprene (natural rubber), (h) traw5-polychloroprene (Neoprene rubber), (i) polystyrene (PS), (j) poly(vinyl acetate) (PVAc), (k) poly(methyl methacrylate) (PMMA), ( ) polycaprolactam (polyamide - nylon 6), (m) nylon 6,6, (n) poly(ethylene teraphthalate), (o) poly(dimethyl siloxane) (PDMS).

Synonyms Acetic acid ethenyl ester Acetic acid ethylene ether Acetic acid vinyl ester Ethenyl acetate Vinyl ethanoate Chemical Formula C4H6O2 Chemical Structure ... 

Besides VC, vinyl ethylene carbonate (VEC), phenylethylene carbonate (PhEC), ° phenylvinylene carbonate (PhVC), catechol carbonate (CC), - ally methyl carbonate (AMC), - allyl ethyl carbonate (AEC), vinyl acetate (VA), and other vinyl compounds, - - acryronitrile (AAN) - and 2-cyanofuran (CN-F), whose chemical structures are given in Fig. 4.10, showed the similar effect and no graphite exfoliation in PC solvent systems. 

Ethylene and vinyl acetate (EVA) are copolymerized using a radical initiator (see Chain polymerization). Figure 1 shows the chemical structure of EVA. The reactivity ratios of both monomers are close to unity, so copolymers have a random structure, and can be prepared with composition ranging from almost 0 to almost 100% vinyl acetate (VA). 

The chemical interaction of organosihcon compounds and copolymers of etltylene with vinyl acetate and copolymers of ethylene with viityl acetate and maleic anhydride was studied by IR spectroscopy absorption and Attenuated Total Reflection (ATR). An emichment of the surface layers of polymers by siloxane phase was found, that may be useful in the design of the chemical structure of adhesive materials for different purposes. 

Figure 8 Chemical structure of ethylene-co-vinyl acetate copolymer.

Poly(Propylene Fumarate) (PPF) is a linear, unsaturated, hydrophobic polyester (Structure 12) containing hydrolyzable ester bonds along its backbone. PPF is highly viscous at room temperature and is soluble in chloroform, methylene chloride, tetrahydrofuran, acetone, alcohol, and ethyl acetate [66]. The double bonds of PPF can form chemical crosslinks with various monomers, such as W-vinyl pyrrolidone, poly(ethylene glycol)-dimethacrylate, PPF-diacrylate (PPF-DA), and diethyl fumarate [67,68]. The choice of monomer and radical initiator directly influence the degradative and mechanical properties of the crosslinked polymer. Once crosslinked, PPF forms a solid material with mechanical properties suitable for a range of bone engineering applications. 

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