Micronized cellulose particles from mechanical treatment and their performance on reinforcing polypropylene composite

Cellulose fibers with different sizes would have wide applications in reinforced polymer composites if their fiber/matrix incompatibility and the processing problem could be overcome. In this study, micronized cellulose particles prepared from fluffy pulp fiber by ball milling are characterized and employed as reinforcing agents for cellulose particle/polypropylene (CP/PP) composites. The effect of cellulose particle size and filler loading on the composite performance are explored. Specifically, the processability, crystallization behavior, tensile property and water absorption of the composite are analyzed. Results reveal that small particles with low aspect ratio and large surface area are beneficial for improving the melting processing ability of the binary blends, promoting the crystallization behavior of the polymer matrix and decreasing the water absorption of the composite specimens. Moreover, composites produced with the milled particles exhibit improved tensile strength, modulus and elongation at break compared with those of the long pulp fiber/PP composite. Incorporation of the coupling agent improves the tensile property and water repellency of the composites due to the increase of interfacial compatibility between hydrophilic filler and hydrophobic matrix.

Automated summary

This study investigates the use of micronized cellulose particles as reinforcing agents for cellulose particle/polypropylene composites. The particle size and filler loading were found to affect the processability, crystallization behavior, tensile property, and water absorption of the composites. Results show that small particles with low aspect ratio and large surface area improve the composite's melting processing ability and promote polymer matrix crystallization, while reducing water absorption. The composites produced with the milled particles exhibit improved tensile strength, modulus, and elongation at break compared with traditional long pulp fiber/PP composites. The addition of a coupling agent further enhances the tensile property and water repellency of the composites by improving the interfacial compatibility between the filler and matrix.