Thermoplastics structure

These resulting polymers are solid, linear, internally cyclized, thermoplastic structures containing unreacted allylic groups spaced at regular intervals along the polymer chain. 

Throne, J.L. Mechanical properties of thermoplastic structural foams, in Wendle, B.C. (ed.) Engineering Guide to Structural Foams, Technomic, Lancaster, PA, USA (1976) pp. 91 -114. 

Thermoplastic structural foams with bulk densities not less than 50% of the solid resin densities are considered. Cellular morphology, uniform-density cell behaviour, the I-beam concept in designing, core-density profile and the role of the skin, mechanical properties, and ductile-brittle transitions are discussed. 63 refs. 

Keywords rheology, fillers, mixing thermoplastics, structure, processing... 

Table 3-1 suimnarizes the physical properties of typical thermoplastic structural foams of 1/8" wall thickness with a 20% density reduction over solid plastics (6). 

Table 3.1 Physical Properties of Thermoplastic Structural Foam (Reprinted from Reference 6, Courtesy of Van Nostrand Reinhold) N) 4s- X 9 O. CT O O PT O -h... 

Brewer, G.W., "Properties of Thermoplastic Structural Foams," pp., 508-513 in Engineering Materials Handbook, Vol. 2 -Engineered Plastics, ASM International, Materials Park, Ohio (1988). 

Foam-Kon. [LNP ICI Advanced Materials] Thermoplastic structural foam cone. for high pressure foam systems, inj. molding compds. 

L.S. Pinchuk and A.S. Mikhnevich. On the substrate effect upon formation of spherulitic thermoplastic structure from melt. Proc. Belarus AS, 1976, Vol. 

Table 7.18 Properties of fV thick thermoplastic structural foam (20% weight reduction)... 

CLASS Polyesters linear aliphatic flexible polyesters thermoplastics STRUCTURE O... 

Hobbs S.Y., 1975, Bubble growth in thermoplastic structural foams, G.E.P. technical information series, nr. 75CRD210... 

Thermoplastic structure polymers with good thermal stability are required. 

They are used for fast assembly of structures designed to be only lightly loaded. Hot melts can be in the form of blocks, rods, granules, powder and film. The adhesive is heated and applied to one surface as a melt loining is then carried out immediately after application and the adhesive cools and develops strength by its consequent solidification. The quicker the surfaces are joined, the better for the bond. Because the bond strength is reached in seconds, the need for clamps of fixtures is eliminated. These adhesives can be used for joints which may subsequendy need to be detached and/or reattached due to their thermoplastic structure. In use however the bonded joint must not be heated up to its melting temperature. 

Two papers point to the use of renewables in the production of interesting polymeric materials based on renewables. The contribution from Kelley describes a model compound study on the reactivity of pyrolysis oils, and how this information can be used in the formulation of new renewables based adhesives. Glasser describes the use of steam explosion technology to facilitate the simultaneous production of lignin and cellulose esters, useful in the production of thermoplastic structural polymers from wood. 

Solvent cements are usually preferable to conventional adhesives for thermoplastic structural foams. Some solvent cements and solvent-containing, pressure-sensitive adhesives will collapse thermoplastic foams. Water-based adhesives based on SBR, polyvinyl acetate, or neoprene are frequently used. Solvent cementing is not effective on polyethylene foams because of their inertness. Recommendations for adhesives for thermoplastic foams are ... 

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