Rigidity of plastics materials

The rigidity of a polymer is determined by the ease with which polymer molecules are deformed under load. In a polymer at -273°C all load is taken by 

Plastics materials, in general are blends of polymers with additives and the latter may well affect the modulus. One simple law of use here relates the modulus of the blend or composite to the modulus of the polymer Ep and of the additive by the equation 

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During this period, the ICI laboratories were also making their other great contribution to the range of plastics materials—the product which they marketed as Perspex, poly(methyl methacrylate). As a result of work by two of their chemists, R. Hill and J. W. C. Crawford, it was found that a rigid transparent thermoplastics material could be produced at a commercially feasible cost. The material became invaluable during World War II for aircraft glazing and to a lesser extent in the manufacture of dentures. Today poly(methyl methacrylate) is... 

Figure 9.3. Stress-strain curves for (a) rigid amorphous plastics material showing brittle fracture and (b) rubbery polymer. The area under the curve gives a measure of the energy required to break the...

A rigid bottle, a collapsible tube, or a flexible pouch made of plastic material may be used for liquid-based topical product. These preparations are marketed in a single- or multiple-unit container. For example, dissolved drug (or any substance, e.g., benzocaine) may diffuse in the suppository base and can, for instance, partition into polyethylene linings of the suppository wrap. 

AX-108 An Update Report on Findings of Fire Study of Rigid Cellular Plastics Materials for Wall and Roof Ceiling Insulation (U-102R). 

In high-pressure agglomeration, another interlocking mechanism may occur if a mixture of rigid and plastic materials is compacted. In this situation, the plastic component flows into recesses and, more generally, envelopes the exterior structure of harder particles, thus producing a strong structural bond that resembles the effect of a matrix binder (see also Section 8.1). 

Mineral microfillers have been tested in a plasticized starch matrix [CAR 01]. For example, micrometric particles of kaolin have been incorporated by extrusion. Due to a significant compatibility between the matrix and the filler, we note an increase in the glass transition temperature, a reduction in water absorption and an increase in the rigidity of the material. However, with the corresponding filler contents, these composites no longer satisfy the standards of biodegradation (at least 90% of the material has to be degraded). 

Plasticizers are the most voluminous additives of semi-rigid and flexible PVC formulations. Their properties, mechanisms of action, and effect on properties of plasticized materials have been extensively discussed in a specialized monographic source, and data on different grades are included in the plasticizer database. ... 

A Fire Study of Rigid Cellular Plastic Materials for Insulated Wall and Roof/ Ceiling Constructions, Factory Mutual Research Corporation, USA, 2000. 

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