S. Yamaguchi

The effects of temperature and liquid crystalline polymer (LCP) on mechanical properties of a blend of polyphenylene sulphide and LCP

The mechanical properties of polyphenylene sulphide (PPS) and liquid crystalline polymer (LCP) blends were investigated over a range of temperatures. The effect of blend composition on the brittle-ductile transition temperature (B-D) was also studied by differential scanning calorimetry and scanning electron microscopy. Blends of various compositions (PPS/LCP; 90/10, 75/25, 50/50 and 25/75) were prepared and injection moulded. The bending test temperature was varied between −40 and 150 °C. The results showed a rapid load drop at the B-D transition region. The B-D transition temperature occurred in unannealed pure PPS, 90/10, 25/75 and 50/50 blends around 75 °C whilst in the annealed sample it was observed around 100 °C. In pure LCP and 25/75, no transition occurred. Partial miscibility of PPS and LCP was confirmed by SEM observations, bending modulus and thermal properties. The use of LCP, as a good reinforcing agent which can improve processability and modulus, is discussed.

Studies of blends of poly(phenylene sulfide) and a liquid crystalline polymer: Time-temperature superposition

Abstract Polymer blends containing poly(phenylene sulfide) (PPS) and liquid crystalline polymer (LCP) of varying compositions were injection molded and tested. Three-point bending tests were carried out on annealed and unannealed samples at various temperatures and strain rates. The time–temperature master curves were constructed by shifting the experimental modulus data at each point of the curves. The increase in bending modulus and reduction of bending strength with increasing LCP content were attributed to the skincore morphology. The time-temperature curves revealed that the bending modulus of the blends can be superimposed over a wide range of temperatures and strain rates.

Surface smoothness of glass mat reinforced polypropylene stampable sheet

Stampable sheets can be made consisting of polypropylene (PP) plies and long glass fibre mat plies. Because stampable sheet is recyclable, and it shows good mechanical properties and processability, it is used for automotive products. However, products made of stampable sheet do not have sufficient surface smoothness, so they are not used for exterior parts that require high surface quality. In this study, the moulding conditions needed for good surface smoothness was investigated. The results indicated that surface smoothness is affected by mould temperature. When the mould temperature was near the melting temperature of the resin, the products had high surface smoothness, but this condition was not appropriate for mass production because it lengthened the production cycle too much Finally, we proposed suitable moulding conditions.