Study On The Preparation And Properties Of Cassava Dregs Biodegradable Composites

With the increasing scarcity of the resources of the earth and the gradual improvement of the human awareness of environmental protection, more and more scholars both at home and abroad are committed to researching a biodegradable material which can take the place of traditional plastic. Plant fiber and starch, or some other natural polymer composites were manufactured to be complete biodegradable material, is a naturally biodegradable material that has developed rapidly in recent years. In this paper cassava dregs fibers were used as raw material, the blending starch and PVA were used as adhesive and enhancer, all the raw materials can be biodegraded, manufactured an environment-friendly, green food packaging materials, which is a new way for the comprehensive utilization of agricultural waste cassava dregs. The research process including processing technology, molding formula, compatibility enhancement, environment characteristics and other aspects1. Based on the single factor experiment, the process of production was optimized by response surface methodology (RSM) to obtain the optimum conditions. It was indicated that the optimum condition was as follows:Temperature,172℃; Pressure,20MPa; Time,15.5min. According to the influence factors of tensile strength, X2(pressure)>X1(temperature)>X3(time).The regression equation describing process of production was obtained by response surface methodology: Y=8.95-0.39X1-0.25X2-0.12X3-1.42X12-2.79X22+0.31X32+0.01X1X2+(7.500E-003)X1X3-0.02X2X3.2. By the L9(34) orthogonal experiment, the appropriate plasticizers have been formulated. The influence of three kinds of plasticizer on starch-PVA system order is: glycerin>H2O>PEG, the optimal formula is H2O10%, PEG10%, glycerin20%, the membrane’s transmittance is24.3%. Starch-PVA membrane’s comprehensive performance is best.3. Blend cassava dregs fibers of different particle size (100mesh,80mesh,60mesh,30mesh,>30mesh) with starch-PVA system. Manufacture composite materials and test their mechanical properties. Experiments show that cassava dregs fibers of60mesh particle size is the best particle size, the tensile strength reached8.95MPa. Compared to the other particle size cassava dregs, it showed better mechanical properties.4. Coupling agent treatment and alkali treatment, these two different surface treatments were used in cassava dregs fibers. The results showed that the two processing methods can improve compatibility and mechanical properties of composites.Three different coupling agent (aluminate coupling agent, titanate and silane) surface modification effect, which were used to manufacture composites, tensile strength of cassava dregs/starch-PVA composites were tested. The results show that the silane coupling agent compared with the other two had better modification effect, the compatibility of cassava dregs/starch-PVA composites has improved significantly. The best dosage of silane coupling agent is3%.From the IR spectrum of unmodified cassava dregs compared with silane modified cassava dregs we can know that the emergence of characteristic peaks showed the cassava dregs had been modified successfully. The weakening of characteristic peak intensity in the IR spectrum of unmodified cassava dregs compared with alkali treatment modified cassava dregs, showed alkali treatment was also effective.5. According to a large number of experiments, the formula of composite material molding process is:cassava dregs fibers:(starch+PVA)=0.4:0.6, starch:PVA=0.8, so cassava dregs fibers:starch:PVA=2:1.33:1.66. The dosage for processing aids is:TalOphr, CaCO34phr, SA5phr, Borax2phr, Liquid paraffin5phr.6. Environment condition has a certain restriction on the use of composite material. When adding5%of liquid paraffin as resistance wet agent, the range of material quality change in the simulation environment humidity is-3%-5%. The adaptability of the composite material in the environment can be improved significantly. The fig microorganism growth progression and fig relation between buried time and material degradation showed reduction of the composite quality and the microbial growth is a positive correlation, after three months, surface of the composite was covered by a lot of microorganisms, quality of materials reduced more than50%.7. In the condition of laboratory mould pressing, explored the foam plant fibers-starch composite. Researched the effects about NaHCO3, Urea, and AC(azo dimethyl amide) foaming agents on bubble morphology in composite. The order about various factors influence on composite density is:AC>NaHCO3>Urea, AC and NaHCO3reached a significant level, the influence of Urea is not significant.