Preparation And Properties Of Waste Polyester/Cotton Fiber Reinforced Composites

With the increasing demand for textiles,the stock of waste textiles is increasing,and the recycling of blended textiles is more difficult compared to pure textiles.In blended textiles,polyester/cotton blended textiles account for more than half,so the development of a suitable process to recycle and reuse waste polyester/cotton blended textiles is essential.Waste polyester/cotton fabrics are usually recycled by mechanical method,physical or chemical method,but mechanical method will cause fiber strength loss and is suitable for low value-added products.Physical or chemical method cannot separate the blended material completely,and the cost is high.To address the above problems,this study had adopted the fibers obtained from the waste polyester/cotton blended fabrics to reinforce general plastics,and prepared waste polyester/cotton fiber reinforced PP and waste polyester/cotton fiber reinforced LMPET composites by mixing and injecting process.The work had also investigated the effects of the waste polyester/cotton fiber content,fiber ratio and fiber length on the properties of the composites.(1)The research on waste polyester/cotton fiber reinforced polypropylene composites:The waste polyester/cotton fiber ratio and the fiber length were invariable,with the increasing of fiber content,the tensile and flexual strength of the composite increased and then decreased,the impact strength increased and the thermal stability became worse.When the fiber content was 30 wt%,the tensile and flexual strength of the composite was the highest,but when it exceeded 30 wt%,the fibers were easy to agglomerate in the matrix,which leaded to the decreased of the tensile and flexual strength of the composite.The ratio of fixed waste polyester/cotton fiber was 65:35,and the fiber length was 8 mm: when the fiber content was 40wt%,the impact strength of the composite was the highest,which was 390.13% higher than that of PP,because the higher the fiber content was,the more energy it took to be pulled out from the matrix,and the greater the impact strength.The waste polyester/cotton fiber content and the fiber length were invariable,because the strength and modulus of cotton were smaller than those of polyester,the smaller of waste polyester/cotton fiber ratio and the higher the cotton content,the worse the mechanical properties of the composite.The waste polyester/cotton fiber content and the fiber ratio were invariable,with the increase of fiber length,the mechanical strength of the composites increased and then decreased,and the thermal stability was basically unchanged.When the fiber length is 8 mm,the mechanical properties of the composites were the best,but when the fiber length exceeded 8 mm,the fibers were easily entangled with each other,and the stress concentration was easy to occur when being stressed,which lead to the decrease of the mechanical strength.On the whole,when the fiber content was 30wt%,the fiber ratio was 95:5,and the fiber length was 8mm,the tensile and flexural strength of the composite was the highest,and the material can be used to prepare tensile and flexural products,such as office desks and chairs.When the fiber content was 40 wt%,the fiber ratio was 95:5,and the fiber length was 8 mm,the impact performance of the composite material was the highest,and the material can be used to prepare impact-resistant products,.such as automobile instrument panels.(2)The research on waste polyester/cotton fiber reinforced low melting point polyester composites:The waste polyester/cotton fiber ratio and the fiber length were invariable,with the increase of fiber content,the mechanical properties of the composites were continuously improved and the thermal stability was gradually deteriorated.Because the fiber had good compatibility with LMPET,when the fiber content was 40wt%,the tensile and flexural strength of the composite was the highest.The waste polyester/cotton fiber content and the fiber length were invariable,the mechanical strength of the composite decreased with the decreased of waste polyester/cotton fiber ratio and increased of cotton.The waste polyester/cotton fiber content and the fiber ratio were invariable,with the increase of fiber length,the mechanical strength of the composite increased and then decreased.On the whole,when the polyester/cotton fiber content was 40wt%,the fiber ratio was 95:5,and the fiber length was 8mm,the tensile,flexural and impact strength of the composite material was the highest,and the composite material can be used to prepare electrical appliances,plastic toys,etc.Comparing the two composite materials,the fiber content increased from 30wt% to 40wt%,the fibers were easy to agglomerate in PP,resulting in a decrease in tensile and flexural strengths,while the fibers had better compatibility with LMPET,and the tensile and flexural strengths continued to increase.And the tensile and flexural strength of LMPET-based composites were higher than those of PP-based composites.Therefore,in the field of high-rigidity materials,LMPET-based composites were more widely used than PP-based composites.