Low density polypropylene/waste cellulose fiber composites by high-shear thermo-kinetic mixer

Official URL: http://dx.doi.org/10.3139/217.3426

Achieving an appreciable weight reduction in PP based com- posite materials, particularly the ones reinforced by glass fi- bers, is quite challenging while enhancing their mechanical properties and fullfilling other enviromental concerns. To ad- dress this issue, low density composites of Poly(propylene) (PP) and waste cellulose fibers (WCF) were produced by high-shear thermo-kinetic mixer. This technique facilitates the ease of processing for the mass production of such com- posite materials due to the availability of high shear rates and relatively short processing times during manufacturing. The structure-property behavior of the molded samples was investigated as a function of WCF content. Briefly, one-fold increase in elastic modulus, 18 % increase in tensile strength, 87% increase in flexural modulus and 27% increase in flex- ural strength of PP were achieved by the addition of 30 wt.% WCF. The significant enhancements in mechanical properties were mainly attributed to the homogeneous dispersion of in- trinsically stiff WCF filler in the PP matrix as a direct result of the high-shear mixing. These results mainly suggest that waste cellulose fibers can be used as an effective reinforcing agent in PP matrix instead of highly dense, non-renewable and non-biodegradable fibers, such as glass fibers, that pre- vents further stresses on the environment. Along with this, the reuse of waste cellulose fiber in PP matrix, particularly at high concentrations like 30 wt.%, evenly corresponds to the reduction of total PP consumption for PP based composite production. The main conclusion of the study is that the exten- sive blending technology gives us the ability to produce high performance thermoplastic based composite materials as well as addressing the world-wide waste disposal problem by reus- ing of natural wastes, which is a great opportunity to ensure sustainability and reduce enviromental and economical costs for many industries.