Preparation of PP/SCF thermally conductive composites with forced-assembled networks by multiple injection compression molding

A multiple injection compression molding (ICM) method was proposed on the basis of injection molding and applied for the preparation of polypropylene/short carbon fiber (PP/SCF) high thermally conductive composites in this article. During each injection compression cycle, the thickness of composite sample would be reduced effectively for better SCF orientation along the flow direction. Moreover, the original loose self-assembled SCF networks obtained from injection process can furtherly transfer into much compact ones under the effect of compression force. The performance differences among SCF/PP composites prepared with one-time injection molding (IM), multiple IM, and multiple ICM were also investigated. The SCF/PP composite sample prepared with multiple ICM method presented superior comprehensive performance, similar to 100% and 28% enhancements in thermal conductivity and tensile strength compared with the one-time IM sample. We believe the multiple ICM method can provide a new idea for industrial production of functional polymer composites, especially for thermoplastic polymer composite.

Automated summary

A multiple injection compression molding (ICM) method is proposed for the preparation of high thermally conductive polypropylene/short carbon fiber (PP/SCF) composites. The method effectively reduces the thickness of the composite samples and improves the orientation of the carbon fibers. The performance of the composites prepared by one-time injection molding (IM), multiple IM, and multiple ICM is compared, and the multiple ICM method shows superior comprehensive performance with significant enhancements in thermal conductivity and tensile strength.