| According to statistics, there are almost 100 million scrap tires every year in China. How to deal with so large number of waste tires is a very critical issue in environmental protection. Lots of waste fibers are by-product during making the waste rubber powder by waste tires. In order to simultaneously recycle waste rubber powder and fiber and solve shock resistant performance problems of the unsaturated resin after curing, the first time the unsaturated polyester / waste rubber powder / tires fiber composites were raised and prepared in this study. Using unsaturated polyester as matrix and adhesive, waste fiber as toughening and reinforcing materials and waste rubber as toughening and filled materials, the environmental composites with good overall performance were gained by adjusting the ratio of these three.In this paper, the waste rubber powder and waste fibers were characterized at first. The results showed that the average size of waste rubber powder is 174.4μm.Test analysis showed that the composition of the waste rubber powder is 62.5 wt% organic matters, 26.3wt% carbon black and 11.18wt% inorganic filler. The rubber groups in the waste rubber powder are natural rubber and butadiene rubber. The studies showed that the diameter of the waste rubber powder is about 30μm and the aspect ratio of that is between 100 um and 150 um. Test results showed that the main compounds of waste fiber are nylon 6 and nylon 66 fibers.In this paper, DMA technique was used to study the curing and post-curing process of the composite. We found that the composites have fast curing speed when the temperature is 135 ~ 150℃; when the composites are cured at 145℃,the gel time is about 17.8min and post cured for 6h at 170℃, the composites have the best performance.We used waste rubber powder to toughen composite materials. TEM and X-ray photoelectron spectroscopy tests showed that styrene monomer can penetrate and cross-link in the powder particles. SEM and TEM tests showed that waste rubber powder pretreated by styrene monomer is more evenly distributed in the resin and the interface of waste rubber powder and resin has become blurred which indicating a good combination of the two-phase. The composite has the best performance when pretreatment time is12h. When the amount of waste rubber powder is15 ~ 20phr, relative to the composites without waste rubber powder, the impact strength raised from 13kJ/m2 to 20kJ/m2, increased by 54%, the toughening effect is obvious and the mechanical properties is best.The mechanical properties of composite have been improved to some degree using different four modifiers on the modification of waste fibers. MF has the best modification effect and the optimal dosage is 6~12phr. When the dosage of modified waste fiber is 120phr, the tensile strength, flexural strength and impact strength of the composites are 21.27MPa, 50.45MPa and 21.29kJ/m2respectively and increased by 73.2%, 35.5% and 19.7% than those without modification. These indicated that waste fibers can enhance the toughness and strength of the composites. IR and microscopic photographs showed the modifier MF can adhere to the surface of waste fiber. DMA test results showed that the modifier MF can enhance the compatibility of waste fibers and the resin and increase the storage modulus of composite. The contact angle test showed that the addition of MF modifier helps to improve the hydrophobic performance. The SEM showed that the addition of MF modifier increases adhesion between fiber and resin, making them combining solidly. And this is the main reason of the mechanical properties increas with adding modifier MF.The heat oxygen aging property of composite was studied. The results showed that the thermal aging of composite base mainly on cross-linking reaction. When the aging conditions are harsher, the degree of crosslink-king is higher and the compatibility among the various components decreased.When the composite were aging at 80℃hot water, tensile strength, flexural modulus and flexural strength were significantly decreased and the impact strength was increased slightly. The significant reasons may be water plasticization, hydrolysis of waste fiber in hot water and formation of hydrogen bonds of unsaturated polyester and water.
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