Preparation of MSBF reinforced PP composites & research on their mechanical and sound insulation properties

Nowadays, most researchers at home and abroad are studying the planting of seashore mallow and the efficient extraction of mallow seed oil, while the remaining mallow stems are generally incinerated or discarded. In fact, there are a lot of bundle fibers in mallow stem bark(MSB), and their physical properties such as strength and modulus are close to those of jute and flax. So developing the fiber-reinforced composites of mallow stem bark fiber(MSBF) has high potential application value. Using mallow stem bark as raw material, MSBF was extracted by alkali degumming process, and MSBF reinforced polypropylene(PP) composites with fiber mass fraction of 40%, 30%, 20%, 10% and 0% were prepared by using alkali-treated MSBF as reinforcement and PP fiber as matrix. The effects of fiber mass fraction on tensile, bending and sound insulation properties of MSBF reinforced PP composites were discussed. The results show that when the fiber mass fraction was 30%, the tensile breaking strength, tensile modulus and bending modulus of the composite were the highest, and the bending strength gradually enchanes with the increase of the fiber mass fraction of MSBF. When the fiber mass fraction exceeds 10%, the voltage peak attenuation rate of MSBF reinforced PP composites increases first and then decreases with the increase of sounding frequency. When the sound frequency is the same, the lower the fiber mass fraction, the worse the sound insulation performance of the composite. When the fiber mass fraction exceeds 30%, the voltage peak attenuation rate decreases.