Plasticization, high molecular

The molar mass distribution within a mean molar mass has analogous effects on the properties and processing of plastics. High molecular moieties increase melt viscosity and improve the mechanical and chemical long-term properties. Low molecular moieties facilitate slipping processes both in the melt and in the solid (reduced long-term stability). 

Plastics and Resins. Plastics and resin materials are high molecular weight polymers which at some stage in their manufacture can be shaped or otherwise processed by appHcation of heat and pressure. Some 40—50 basic types of plastics and resins are available commercially, but HteraHy thousands of different mixtures (compounds) are made by the addition of plasticizers, fillers, extenders, stabilizers, coloring agents, etc. 

The remaining tailings left over from the clay fractionation step is either flocculated with alum, high molecular weight polymers, or a weak (pH 3.0) solution of sulfuric acid, and stored in settling ponds as waste, or may be filtered and sold to the brick industry as a coating material. It also may be dried and sold as a filler in plastics and textured paint (qv). 

Studies on the use of high molecular weight esters in nitrile mbber have led to further studies to compare DINP with DBP. These showed that at the 10 phr level the nitrile mbber was effectively plasticized with DINP (35). 

CPA. Copolymer alloy membranes (CPAs) are made by alloying high molecular weight polymeries, plasticizers, special stabilizers, biocides, and antioxidants with poly(vinyl chloride) (PVC). The membrane is typically reinforced with polyester and comes in finished thicknesses of 0.75—1.5 mm and widths of 1.5—1.8 m. The primary installation method is mechanically fastened, but some fully adhered systems are also possible. The CPA membranes can exhibit long-term flexibiHty by alleviating migration of the polymeric plasticizers, and are chemically resistant and compatible with many oils and greases, animal fats, asphalt, and coal-tar pitch. The physical characteristics of a CPA membrane have been described (15). 

Polystyrene [9003-53-6] (PS), the parent of the styrene plastics family, is a high molecular weight linear polymer which, for commercial uses, consists of - 1000 styrene units. Its chemical formula (1), where n = - 1000, tells htde of its properties. 

Because plastics are almost invariably modified with one or more additives, there are three components of chemical analysis the high molecular weight portion, ie, the polymer the additives, ie, plasticizer and mold-release agent and the residuals remaining from the polymerization process. The high... 

Functional polyethylene waxes provide both the physical properties obtained by the high molecular weight polyethylene wax and the chemical properties of an oxidised product, or one derived from a fatty alcohol or acid. The functional groups improve adhesion to polar substrates, compatibHity with polar materials, and dispersibHity into water. Uses include additives for inks and coatings, pigment dispersions, plastics, cosmetics, toners, and adhesives. 

Ethyl Vinyl Ether. The addition of ethanol to acetylene gives ethyl vinyl ether [104-92-2] (351—355). The vapor-phase reaction is generally mn at 1.38—2.07 MPa (13.6—20.4 atm) and temperatures of 160—180°C with alkaline catalysts such as potassium hydroxide and potassium ethoxide. High molecular weight polymers of ethyl vinyl ether are used for pressure-sensitive adhesives, viscosity-index improvers, coatings and films lower molecular weight polymers are plasticizers and resin modifiers. 

The concept of a photoresist is of great antiquity and has a number of features of interest relating to plastics. In Ancient Egypt mummies were wrappted in linen cloths dipped in a solution of oil of lavender containing high molecular mass bituminous material (Chapter 30) which was known variously as Syrian Asphalt or Bitumen of Judea. On exposure to light the product hardened and became insoluble. The evidence is that some form of cross-linking occurred. 

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