Plastics thermosets

The two primary types of plastics, thermosets and thermoplastics, are made almost exclusively from hydrocarbon feedstocks. Thermosetting materials are those that harden during processing (usually during heating, as the name implies) such that in their final state they are substantially infusible and insoluble. Thermoplastics may be softened repeatedly by heat, and hardened again by cooling. 

This change is signihcant in that most components of MSW are either biodegradable or recyclable with relatively modest effort. For example, glass, paper, and metals have been recycled for decades. By contrast, the recycling of plastics is more difficult partly because there are so many different kinds of plastic and partly because some plastics (thermosetting plastics) cannot he remelted, an important hrst step in any recycling process. 

Cross-linking The formation of side covalent bonds linking different polymer chains and therefore increasing the rigidity of, say, a plastic. Thermosetting plastics are usually heavily cross-linked. 

Thermosetting plastics Thermosetting plastics can be heated and moulded only once. 

Rosato, D. V., Materials Selection Reinforced Plastics-Thermosets in Concise Encyclopedia of Polymer Science and Engineering, J. I. Kroschwitz (ed.), Wiley, 1990. 

L-S-139, Screening, Plastic, Insect, August 22, 1950. Amendment-1, August 29, 1952. L-T-0041 (GSA-FSS), Table Top Assemblies (Plastic Thermosetting Resin Laminate), ... 

AB. [Cuyahoga Plastics] Thermoset polyester, some glass or mineral inforced ... 

Elastocarb . [Morton Int l.] Magnesium carbonate filler providing flame retardancy and smcdce suf nession to elastomers, plastics, thermosets for conduit, wire and c le conqpds., aircraft interior parts, film and sheet... 

Tacti [Dow Plastics] Thermoset performance polymers for aerospace applies. 

Yersamag . [Morton Int l.] Magnesium hydroxide filler, fire retardant smoke suppressant fex plastics, thermosets, dastomers. 

SO 2577. Plastics Thermosetting moulding materials Determination of shrinkage. 1984. 

ISO 11248, Plastics—Thermosetting moulding materials—Evaluation of short-term performance at elevated temperatures, 1993. 

When immersed in alcohol or acetone, the plastic will swell but is virtually insoluble and is referred to as B-stage. See A-B-C stages phenolic plastic thermoset plastic. 

There are many thousands of plastics, each with specific chemical and physical characteristics which will affect the performance of the product. There can be vast differences in processing these plastics. First the designer must choose between two basic types of plastic, thermosets and thermoplastics. 

CAS 471-34-1 EINECS/ELINCS 207-439-9 Uses Pigment, filler, extender, reinforcer, and bodying agent in plastics (thermoset polyester, PVC), vinyl plastisols, rubber (NR, SBR, CR, HR), adhesives, sealants, caulks, paints, coatings, printing inks, extrusions, moldings, belts, footwear chem. reagent, carrier, calcium source Features Nonabrasive controlled particle size easily dispersed Properties Powd. 0.8 p median particle size 0.015% on 325 mesh ... 

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