Dynamically Cross-Linked Tannin as a Reinforcement of Polypropylene and UV Protection Properties

Tannins were used as reinforcing components for polypropylene with anti-UV properties via dynamic curing extrusion. The influence of cross-linked tannins in different weight fraction and their anti-UV capacity on morphological, mechanical, rheological, crystallize and thermal properties were studied. The experimental results indicated that the cross-linked tannins improve Young’s modulus, crystallinity, and thermal stability and reinforce the internal network of polypropylene. After UV accelerated weathering, polypropylene had fewer surface cracks, lower carbonyl index, fewer crystallinity decreases and less mechanical properties loss with increasing tannin content.

Study on the Cure Kinetics of Middle Temperature Curing 3234 Epoxy Resin System

The cure kinetics of middle temperature curing 3234 epoxy resin was investigated under both isothermal and dynamic curing conditions by Differential Scanning Calorimetry (DSC) technique. The kinetic equations for isothermal and dynamic curing were established respectively by analyzing experimental data obtained from DSC . By following the temperature procedure of the standard cure cycle of the resin system, the validity of the cure kinetic equations was verified by means of determining the residual heat of reaction of samples from different stages of the cure cycle. Results showed that the cure kinetics under both isothermal and dynamic conditions could be described by the autocatalytic kinetic model. Predictions by the kinetic equation for dynamic curing agreed well with the experimental results.