| Cellulose acetate (CA) synthesized from plant fibers is one of eco-friendly materials. The excellent optical property and the mechanical property of CA make it widely used as a cellulose derivative. But the low melt flow rate, the bad thermostability that means it is easy to decomposition during heating, and other issues in the melt processing process greatly limits its application in a few fields. This paper mainly studied the effects of adding plasticizers on the CA and prepared CA/plasticizer modified material. Adding plasticizers was in order to reduce the glass transition temperature to improve processing performance. And then organo montmorillonite (OMMT) as intercalation layer was added to modify the CA. The different properties of modified CA were researched through the HAAKE torque rheometer, the capillary rheometer, the X-ray diffraction, the scanning electron microscopy, the infrared spectroscopy, the mechanical performance tester and other text methods.The details on research were as follows:By comparing with the effects of diethyl phthalate (DEP), triethyl citrate (TEC), triethyl citrate (DBP), epoxidized soybean oil (ESO), triphenyl phosphate (TPP), triacetin plasticized on the CA found that only DEP, TPP, and triacetin can plasticize CA, and the order of plasticizing efficiency was triacetin, DEP, TPP. As the plasticizer contents increased, the tensile strength, all of the flexural strength and the flexural modulus decreased gradually, but the elongation at break increased. When the content of plasticizers was in a certain, the order of the heat resistance property was TPP> DEP > triacetin. The certain amount of the plasticizer which is 30% not only could improve the processing flowability of CA, but also maintained high rigidity. The material possessed better combination properties.On the condition of the plasticizer addition amount was 30%, the triacetin complexed with DEP as one kind of plasticizer was investigated and found that in the mixed plasticizer with the triacetin content increased, the melt flow rate became large, the bending strength and the flexural modulus decreased first, the tensile strength and the elongation increased at first and then decreased, when the ratio of the triacetin and the DPE in the mixed plasticizer was 2:1, the synergies effect was the most obvious.Using different molecular weight PEGs as plasticizers to plasticize CA, the results showed that the larger the molecular weight of PEG was, the lower melt fluidity and the worse the processing performance were. PEG-800 could not plasticize CA. As the increase of molecular weight, the tensile strength decreased, the elongation increased and then decreased. The highest elongation appeared in the material with PEG-200. The migration rate of PEG from the CA declined as the molecular weight increased. The high molecular weight also leaded the thermal evaporation of plasticizer during the second phase of heat weightlessness to shifted to higher temperatures.The organic montmorillonite (OMMT) was added to the modified CA which contented 30% DEP preparing CA/DEP/OMMT nanocomposites. The analysis tests reflected that the lamellar spacing in OMMT increased, the molecular chain of CA intercalated into the OMMT layer, and with OMMT contents increased, the melt viscosity increased and then decreased, the tensile strength decreased, firs of all the elongation t increased and then decreased, thge Vicat softening point increased and then decreased. The maximum of the properties were appeared at the CA/DEP/OMMT nanocomposites with 0.4wt% OMMT. |
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