Abstract: The present invention provides a high-strength and high-heat-resistant bio-based polyamide composition, which consists of the following parts of materials by mass: 43.50-89.95% of bio-based polyamide resin slices; 10-50% of reinforcements; 0.01-2% of rare earth compounds; 0.01-1% of copper salt antioxidant combinations; 0.01-1% of free-radical scavengers; 0.01-0.5% of heat-conducting masterbatches; 0.01-1% of stabilizers; and 0-1% of dispersants. The advantage of the present invention is presented in that: the bio-based polyamide resin slice is prepared through a stepwise polycondensation process of pentanediamine and adipic acid, or through a stepwise polycondensation process of pentanediamine, adipic acid and terephthalic acid and the pentanediamine is prepared through fermentation of starch, so the prepared polyamide resin pertains to an environmentally-friendly engineering plastic.

Abstract: The present invention provides a class of thermotropic liquid crystalline polyesters (TLCPs) and molding compositions comprising the polyesters and glass fiber. The TLCPs consist essentially of repeat units derived from p-hydroxybenzoic acid (HBA), 6-hydroxy-2-naphthoic acid (HNA), terephthalic acid (TA), and hydroquinone (HQ), and the mole percent of HBA, HNA, TA and HQ is 34-72%, 12-26%, 4-21% and 4-21%, respectively. The TLCPs have a melting temperature equal to or below 355° C., an inherent viscosity of 4.0-10.0 dL/g and a Heat Deflection Temperature (HDT) in the range of 260-285° C. when compounded with 30% by weight glass fiber. The optimum compositions, selected from the above-mentioned compositional ranges exhibit a relatively low melting temperature and a relatively high HDT. Specified compositions, selected from the above-mentioned compositional ranges have low melting point, which are useful to blend with conventional polymers such as poly (ethylene terephthalate) and nylon etc.