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The effects of methanol/gasoline mixtures on swell properties and tensile properties of selected automotive elastomers were investigated. Two gasolines with aromatic contents of 30% and 50% were used in the investigation. Equilibrium swell measurements and tensile measurements were conducted using ASTM standard procedures. The results show that although few elastomers were affected drastically by pure gasoline (e.g. natural rubber) and a few by methanol (e.g. fluorocarbon elastomer) most of the elastomers were more severely affected by mixtures of the gasoline and methanol rather than the pure components. Presence of higher aromatic content in the methanol/gasoline mixtures led to additional deterioration of properties. The data on all elastomers except the fluorocarbon can be explained in terms of the solubility parameter concept.

Sixteen automotive elastomers were investigated in the methanol/gasoline system. The results show that although few elastomers are affected drastically by pure gasoline (e.g., natural rubber) and few by the pure methanol (e.g., Viton), most of the elastomers are severely affected by mixtures of the gasoline and methanol rather than the pure components. Results on the ethanol/gasoline system are similar to those of methanol except that the ethanol mixtures have slightly less severe effects. Only in the case of Viton a greatly reduced effect in the ethanol system was observed. In comparing the results of the different elastomers it was found that several of them swell less and retain more of the tensile strength after aging in alcohol/gasoline mixtures than nitrile. These elastomers include fluorocarbon elastomers (Viton), fluorosilicone, polysulfide, F-70A polyether, polyepichlorohydrin homopolymer, and polyester urethane.

The intumescent material described in this paper expands under high heat or fire conditions to form an insulating sponge. Its composition is based on a blend of high-density polyethylene and chlorinated polyethylene. The material is processed using normal plastic techniques. Tensile properties, heat aging, fluid aging, and thermal properties have been evaluated and are presented. Fire testing using a 1000 °C Bunsen burner as a source, showed that the material does not drip or burn through, even after 30 minutes of exposure. Prototype fire shields made of the intumescent material have been tested on fuel tanks, bulkheads, and wheel well covers. In all cases the intumescent material provided excellent protection. Similar applications are identified for airplanes, motorcycles, industrial and residential buildings. The material is recyclable and can be made from recycled polymers.

The materials used for making plastic fuel tanks are: virgin high-density polyethylene; fuel tank regrind; ethylene vinyl alcohol copolymer (EVOH) fuel barrier; and maleic anhydride modified linear low-density polyethylene adhesive. Impact strength measurements were conducted per ASTM D256 using Izod & Charpy machine configurations. All polymers were found to have superior impact resistance at room temperature. The polyethylene and fuel tank regrind maintain superior impact at −40 °C; however, a sharp drop in impact resistance is noted for EVOH. Dynamic mechanical analysis (DMA) of EVOH showed that in addition to the glass transition at about 70 °C, the polymer undergoes a second order transition around −35 °C, which is responsible for embrittlement. All materials are sensitive to the presence of notches or sharp discontinuities. Notched Izod impact resistance is five to ten times lower for polyethylene matrices; and forty times lower for EVOH than unnotched samples.

A new method has been developed for measuring the thermal conductivity of polymeric materials. The method is based on heat capacity measurements made using modulated differential scanning calorimetry (MDSC). This technique is capable of quantitatively separating reversible (heat capacity related) thermal events from nonreversible thermal events. The advantages of the method are that it is fast and leads to accurate thermal conductivity measurements. The new method was used to measure thermal conductivity of 43 polymeric parts. The results show that crystalline polymers have higher thermal conductivity than amorphous polymers. For any one polymer, thermal conductivity increases with an increase in filler concentration.