ABSTRACT
Cellulose and its derivatives are widely explored for films and thickening of pharmaceutical solutions, in paints, as reinforcement in composites, among others. This versatility is due to advantages such as renewability, low cost, and environmental friendliness. When used in polymer composites, due to the hydrophilic character of the cellulose, surface chemical modification is highly recommended to improve its compatibility with the polymeric matrix. Hence, this paper presents a systematic review of chemically modified cellulose/epoxy resin composites focusing on the last five years. The investigation followed the PRISMA protocol that delivers a meticulous summary of all available primary research in response to a research question. After including/excluding steps, thirty-six studies were included in the review. The results were presented focusing on thermal, mechanical and dynamic-mechanical properties of the composites. In brief, this methodology helped identifying the main gaps in knowledge in that field.
ABSTRACT
Microcrystalline cellulose (MCC) can be a reinforcement in composites, especially after surface modification. In this paper, MCC was modified using 3-aminopropyltriethoxysilane (APTES) in the following ratios (MCC/APTES): 1:3, 1:4, 1:5, 1:10). The MCC morphologies did not change with the treatment even though the distribution of APTES over the MCC surface varied. FTIR analysis showed MCC and APTES characteristic peaks for all samples. The crystallinity index (CI) decreased with the APTES ratio. The non-isothermal kinetic degradation by thermogravimetric analysis in different heating rates was studiedin order to evaluate the kinetic triplet: activation energy Ea, exponential factor (A), and reaction order (f(α)). The Ea dependence on conversion degree was not affected, but two degradation steps were observed for all samples. Ratios up to 1:4â¯suggested two consecutive autocatalytic degradation mechanisms. The 1:5 and 1:10 ratios caused a change in the most probable degradation mechanism for nucleation followed by autocatalytic degradation mechanism.
