Study On Preparation And Performances Of Fiber-Amino Resin Molding Compounds

With the world energy crisis and environmental protection for human being,"Biomass polymers", prepared from renewable sources with the aid of modern theories and technologies, have attracted much attention, as they can substitute some petroleum derived plastics. Biomass resources are rich in China. Forestry waste produces more than 7 billion straw alone annually, but most is burned, which causes waste of resources and serious environmental pollution. Amino molding compounds, with excellent performance, produced from agricultural and forestry waste materials, can not only achieve the aim of waste utilization, but also reduce the cost of molding compounds.Amino molding compounds were prepared from agricultural and forestry waste materials. The preparation and properties of a variety of amino molding compounds and effects of plasticizersand curing agents on the performance of molding compound were investigated. The major results were described as follows:1. MUF molding compounds were prepared from corn stalk fiber as reinforced materials and MUF resin as polymeric matrix. The effects of corn straw fiber content on bending strength, impact strength of molding compounds were investigated. The internal-surface bonding performances of fibers and MUF resin were characterized by SEM. The mechanical properties and thermal stability were analyzed by DMA and TGA. The results showed that the mechanical properties of molding compounds were excellent, while the corn straw fiber had a content of 31%, with a bending strength of 60.41MPa and an impact strength of 1.81KJ/m2. The storage modulus and comprehensive mechanical properties were excellent. The compatibility between corn stalk fiber and MUF resin was poor. The weight loss rates of molding compounds increased from 0.5% to 2.0% when the temperature increased from 68.8℃to 114.3℃. The rates increased up to 26% when the temperature increased to 246.0~345.2℃. The effects of corn straw fiber content on the thermal stability of molding compounds were insignificant. 2. MUF molding compounds were prepared from wheat straw fiber as waste materials. The straw fiber was processed by alkali, acid, KH550 and KH370. The performance of the molding compounds, such as flow behavior, molding shrinkage and mechanical properties, could be altered by using a variety of treatment conditions and additives. The results showed that denaturants not only opened or swelled the fibers to increase the wettability to the straw surfaces, but also exposed more sites for cross-linking of the resins. The alkali produced excellent performance of molding compounds, which were enhanced with straw fiber using KH550 coupling. The flow was enhanced by 16%. The molding shrinkage decreased by 47%. The bending strength was 87.63MPa, and the impact strength was 1.98kJ/m~2. Generally mechanical properties and thermal stability were obviously improved.3. Polyethylene Glycol 6 000, polyethylene-wax, triphenyl phosphate, and para-toluenesulfonamide were used as plasticizers for molding compounds. The effects of different plasticizers on fluidity and mechanical property of molding compounds were studied. The dynamic mechanical properties of molding compounds were also tested by DMA. The result showed that all of four plasticizers improved the flow properties of molding compounds. The comprehensive property of molding compounds was excellent when the content of Polyethylene Glycol 6 000 was 1.0~3.0 copies. The bending strength was enhanced by 6.0%.The impact strength decreased by 14.9%. The fluidity decreased by 10.0%.4. The effects of the ammonium chloride content, triammonium citrate, ammonium sulfamate, ammonium chlorideand ammonium sulfamate, ammonium chloride and potassium aluminum sulfate curing agents on flow, molding shrinkage, mechanical properties of molding compounds were studied. The results showed that the performances of molding compounds were excellent, while the ammonium chloride content was 1.5 copies, with the fluidity of 142mm, and the molding shrinkage rate of 0.31%, and the bending strength of 98.62MPa, and the impact strength of 1.98kJ/m~2. The dynamic mechanical analysis was excellent. The effects of ammonium sulfamate were better with the molding shrinkage of 0.26%. The dynamic mechanical properties were the best. The cure effect of bi-component curing agents was universal.