Composites of Unsaturated Polyester Resins with Microcrystalline Cellulose and Its Derivatives

Abstract

The paper investigates the properties of unsaturated polyester resins and microcrystalline cellulose (MCC) composites. The influence of MCC modification on mechanical, thermomechanical, and thermal properties of obtained materials was discussed. In order to reduce the hydrophilic character of the MCC surface, it was subjected to esterification with the methacrylic anhydride. This resulted in hydroxyl groups blocking and, additionally, the introduction of unsaturated bonds into its structure, which could participate in copolymerization with the curing resin. Composites of varying amounts of cellulose as a filler were obtained from modified MCC and unmodified (comparative) MCC. The modification of MCC resulted in obtaining composites characterized by greater flexural strength and strain at break compared with the analogous composites based on the unmodified MCC.

Thermal Degradation Kinetics of ZnO/polyester Nanocomposites

“…In the case of the nanocomposites, the rubbery plateau tended to reach zero after the transition region, which should imply that the ZnO nanoparticles favor the curing process of the polyester resin [ 3 , 34 , 35 ], which is in agreement to the FTIR results previously shown.…”

“…The second one is appreciated in the rubbery modulus region, where the polyester develops a notorious shoulder from 90 to 160 °C, afterwards the curve tends to zero. Since this signal is related to the crosslinking density, which is activated by effect of temperature, this kind of shoulder should be related to the partial curing process [ 3 , 34 , 35 ]. The behavior developed by the UPR allows one to consider that additional curing of the unsaturated polyester is occurring.…”

Development and Characterization of Sustainable Composites from Bacterial Polyester Poly(3-Hydroxybutyrate-co-3-hydroxyhexanoate) and Almond Shell Flour by Reactive Extrusion with Oligomers of Lactic Acid

“…Despite high polarity ester groups can establish somewhat interactions with polar groups in cellulose, the main compatibilizing effects are obtained with high reactive groups such as maleic anhydride, carboxyl acids, end-chain hydroxyl groups, glycidyl methacrylate as reported by Pracela et al [46] by using functionalized copolymers to provide increased interface interactions between a polymer matrix and cellulose particles. Some interactions between ester groups and cellulose particles have been described by Chabros et al [47] in thermosetting unsaturated polyester resins with cellulose fillers; in particular they describe some interactions between the polar ester groups and hydroxyl groups in cellulose by hydrogen bonding. These small range interactions can also occur in PHBH/ASF composites, but their intensity is lower than that provided by the reaction of carboxylic acid and hydroxyl terminal groups in OLA with both hydroxyl groups in cellulose and PHBH through condensation or esterification reactions.…”

Synthesis, Characterization and Testing of Antimicrobial Activity of Composites of Unsaturated Polyester Resins with Wood Flour and Silver Nanoparticles

“…Greater concern about health as a result of industrial activities enhances the demand for unsaturated polyester resins. Modern products use a low content of styrene, which reduces the harmful effects of workmen’s exposure to poisonous gases, and thus decreases carbon dioxide emissions improving safety standards in many industries [ 6 ]. Such materials are widely applied in the production of yachts, kayaks, sailboats, bathtubs, shower cabins, etc., as well as housing goods and medical equipment.…”