Research On Vegetable Oil-based Polymers Reinforced With Modified Microcrystalline Cellulose

Vegetable oil-based polymer is a kind of new environmental friendly biomaterial, but it need to be reinforced because of the shortcomings such as poor mechanical strength and toughness. Microcrystalline cellulose(MCC) has the advantages of low density, the hydroxyl activity, renewability and biodegradability. There is no doubt that MCC can effectively improves the properties of vegetable oil-based polymers. However, there were problems that MCC had bad dispersion and poor compatibility with vegetable oil-based polymer when using it as a reinforcement.In this study,to improve the compatibility of MCC with vegetable oil-based polymer, dialdehyde cellulose(DAC) was oxidized from MCC; octadecyl isocyanate grafted MCC(18c-g-MCC) and hexamethylene diisocyanate grafted MCC(HDI-g-MCC) were prepared by modification reactions of grafting isocyanate to MCC. Modified MCC was used to reinforce the ESO polymer and the castor oil-based polyurethane(COPU). Finally, the ternary composite material ESO polymer/COPU/MCC was prepared, reinforced and to ughed simultaneously at the same time by MCC and the elastomer, COPU. In this study, the main characterized methods were scanning electron microscope(SEM), fourier transform infrared spectrometry(FTIR), X-ray diffraction(XRD), dynamic mechanical analysis(DMA), mechanical properties testing, thermal stability analysis, contact angle testing and water absorption testing. Conclusions based on this research were shown as follows:1. Research on ESO polymer reinforced with MCC or DAC : DAC was prepared by the oxidation of MCC. MCC or DAC reinforced ESO polymer were prepared. The results showed that the addition of MCC or DAC can improve the mechanical properties of the composites. When the content of MCC was 20wt%, the impact strength and notched impact strength of ESO polymer/MCC composite materials were the best of 40.95 KJ/m2 and 9.57 KJ/m2, which were higher than the ESO polymer by 169% and 145% respectively; Tensile strength reached the maximum value of 10.63 MPa, increasing by 100%. The tensile strength and impact strength of ESO polymer/DAC composites were more excellent than ESO polymer/ MCC composites. With the increase of cellulose content, Tg of the two kinds reinforced composites increased, the hydrophily and water absorption were both enhanced.2. The research results show that the 18C-g-MCC and ESO polymer has a good interfac ial compatibility. As expected that, the tensile strength, impact strength and elongation at break of the ESO polymer/18C-g-MCC composites were much better than the ESO polymer, increasing by 670%, 670% and 400%, respectively. With the increase of the content of cellulose, Tg of the ESO polymer/18C-g-MCC composites increased, however, hydrophilicity and water absorption were lower compared with ESO polymer/MCC composites.3. Research on COPU reinforced respectively with MCC, 18C-g-MCC and HDI-g-MCC: firstly, the tensile strength, elongation at break and hydrophilicity increased when adding MCC to COPU; MCC had good interfacial compatibility with the COPU matrix after modification, which increased the lipophilicity of MCC. As a result of that modification, the mechanical properties, thermal stability, dynamic mechanical properties and hydrophobic properties of the COPU/HDI-g-MCC composites were improved greatly, as well as the COPU/18C-g-MCC composites.4. Research on ESO polymer/COPU/MCC composites: the ternary composite material ESO polymer/COPU/MCC was prepared, reinforced and toughed simultaneously at the same time by MCC and the elastomer, COPU.The research results show that the tensile strength of ESO polymer/COPU/MCC composites increased by 200% than the ESO polymer/COPU composite, the elongation at break increased by 16.9%, impact strength and notched impact strength increased by 132.6% and 191.4% respectively. Along with the increase of the content of MCC, Tg and hydrophilicity of ESO polymer/COPU/MCC composites increased.