Plasticizers monomeric types

The polymeric plasticizers are used where permanence is of prime importance. The molecular weights of these plasticizers vary quite extensively. Variations from under 850 to 8000 are not uncommon. The cost of polymeric plasticizers is usually in excess of that of the normal monomeric types. Resistance to extraction by soapy water, oils, and migration into nitrocellulose, polystyrene, and rubber are usually superior with polymeric plasticizer systems. Because of their higher viscosities, they are usually more difficult to handle. 

Monomeric types It is common to characterize plasticizers generally as either polymeric or monomeric. For our purposes here, monomerics are all plasticizers (glycol esters, monoesters, diesters, and triesters), which are not polymeric. Viscosities range from 4 to 400 cps. 

Other Low-Volatility Monomeric Plasticizers Aside from phthalates, trimellitates, and epoxidized oils, the only other low-volatility monomeric-type plasticizers currently available are shorter-chain fatty acid esters of pentaerythritol (PE) and dipentaerythritol (DPE). The PE ester is in the molecular weight range of the trimellitates and DTDP and thus has comparable volatility to these types of plasticizers. The DPE ester (actually a blend of PE and DPE esters) approaches the higher-molecular-weight range of the epoxidized oils. Both of these products are characterized by low viscosity. 

Production of all types of vinyl resins, exclusive of plasticizers and fillers, during 1941 to 1950 are presented in Figure 2. These totals are for production of all polymers customarily classified as vinyl resins, including polyvinyl chloride, copolymers of vinyl chloride with vinyl acetate or vinylidene chloride, or modified polymers derived from them. However, the principal monomeric raw material for this field of resins is vinyl chloride. 

Plasthall [Hall]. TM for a broad range of monomeric and polymeric plasticizers used in polymers and elastomers. Types include adipates, gluta-rates, trimellitates, azelates, sebacates, and tallates. 

Polyethylene. A thermoplastic produced by polymerization of ethylene. Polyethylene has the greatest bulk of all plastics in terms of both production and consumption. Several industrial processes are used for the polymerization of ethylene. Characteristics of polyethylenes produced in different ways are similar but not quite identical. All of them are microcrystalline translucent (seemingly transparent in thin layers) thermoplastics with a lower density than that of water, low permittivity and dielectric loss, and high resistance to acids and alkali. The different types of polyethylenes are principally classified by density. Low-density polyethylene (LDPE) has a rather branched carbon chain with repeated — CHg—CHg— monomeric units and a density of 0.918 to 0.935 g/cm, while the almost linear high-density polyethylene (HOPE) has... 

This adhesive group has been promoted for use as a sealant. The adhesives used are acrylate acid diesters (polyester-acrylic). They are essentially monomeric thin liquids that polymerize to form a tough plastic bond when confined between closely fitting metal joints. Contact with air before use keeps the monomeric adhesive liquid. Metal surfaces accelerate the polymerization in the absence of air (anaerobic conditions). These materials will bond all common metals, glass, ceramics, and thermosetting plastics to each other. Phenolic plastics and some plated metals, such as cadmium and zinc, require a primer such as ferric chloride. Polymerization is essentially a free-radical-type addition polymerization. " ... 

PEBAs are plasticizer-free TPEs. The soft segment is the polyether and the hard segment is the polyamide (nylon). They are easy to process by injection molding and profile or film extrusion. Often they can be easily melt-blended with other polymers, and many compounders will provide custom products by doing this. Their chemistry allows them to achieve a wide range of physical and mechanical properties by varying the monomeric block types and ratios. 

In reinforced plastics various inorganic materials are dispersed in the polymer. Carbon black reinforced elastomers have already been considered see Section 9.16.2. For fiber composites, two subtypes are important, the short fiber-containing materials, which are thermoplastic, and the continuous filament types, which cannot flow. While short fibers can be melt blended with thermoplastics, they are often embedded in monomeric mixes, followed by polymerization in situ. Continuous fibers are always processed via monomeric mixes which can flow over the beds of fibers. Of course, these monomeric mixes may have polymers or prepolymers dissolved in them, raising the viscosity, and reducing shrinkage on polymerization. An example of the continuous filament type is a tape composite, familiar as the strapping tape used for packaging. 

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