Synthesis and characterization of methyltetrahydrophthalic anhydride esterified corn starch by wet method

The main purpose of this paper is to synthesize a novel esterified starch with an alicyclic structure. Herein, methyltetrahydrophthalic anhydride (MeTHPA), an alicyclic anhydride, was used to synthesize esterified corn starch (CS) with different degrees of substitution (DS) by a wet method. Compared with CS, the crystallinity and thermal degradation temperature of MeTHPA esterified CS (MeCS) decreased, while the hydrophobicity and light transmittance of MeCS films increased. The esterification modification significantly improved the toughness of the starch film. Between CS and MeCS films, the 15% Me/CS film shows a maximum elongation at break of 24.2% and a tensile strength of 8.0 MPa. Furthermore, 15% Me/CS was blended with CS as a sizing agent for polyester/cotton blended yarns and showed significantly increased adhesion to the blended yarns. Hence, the CS blended MeCS has a potential application in wrap sizing.

EPOXY POLYMERS BASED ON DIGLYCIDYL ETHERS WITH CYCLIC GROUPS

Glycidyl ethers of polycyclic bisphenols of norbornan type and their phenyl substituted derivatives were obtained and studied. They were solidified by diaminodiphenylsulphon and methyltetrahydrophthalic anhydride. The data of the termogravimetric analysis of the obtained polymers showed that they are characterizes by high thermal – and heat stability.The properties of polymers depend on the structure of the hardener and its chemical nature as well. The properties of polymers were sharply changed when glycidyl derivatives of bisphenols were cured by hardeners of different chemical structure. The presence of cyclic structures in the hardener molecule causes considerable increase of their thermal stability. Polymers on the basis of chlorine substituted glycidyl ethers of polycyclic bisphenols are characterized by incombustibility.

Bio-Based Epoxy Resins Based on Linseed Oil Cured with Naturally Occurring Acids

Structural properties of resins based on epoxidized linseed oil (ELO) were investigated in reference to varying amounts of the hardener components methyltetrahydrophthalic anhydride (MTHPA), pyromellitic dianhydride (PMDA) and maleic acid (MA). This includes gel time and the Shore A and D hardness. The shortest gel time of 0.9 min and the highest Shore A and D hardness of 85 and 34 were found at a nMTHPA/nPMDA/nMA molar ratio of 8/1/8. To study the effect of the ELO mass on gel time and hardness, different masses of ELO (8, 10, 12, 14 and 16 g) were used, keeping the amount of the hardener system (4 g) (MTHPA, PMDA and MA) constant. With increased ELO mass, gel time increased while the Shore A and D hardness of the samples did not differ when up to 14 g ELO was applied. Substitution of petrol-based PMDA with biogenic compounds, specifically oxalic acid and citric acid, resulted in new bio-based epoxy resins with shorter gel times while maintaining hardness.

Effect of an Anhydride Excess on the Curing Kinetics and Dynamic Mechanical Properties of Synthetic and Biogenic Epoxy Resins

This work analyzes the effect of the anhydride excess on the nonisothermal curing kinetics and on the final properties of synthetic and biobased epoxy resins. Diglycidyl ether of bisphenol A (DGEBA) and epoxidized soybean oil (ESO) were crosslinked using methyltetrahydrophthalic anhydride (MTHPA) as a curing agent and 1-methylimidazole (1MI) as an initiator. It was shown that the ESO/MTHPA/1MI system reacts slower than the DGEBA/MTHPA/1MI system, giving place to a more significant evaporation of the curing agent during the reaction. As a result, an excess of anhydride improves the final thermal properties of the ESO/MTHPA/1MI network, contrary to the behavior observed for DGEBA/MTHPA/1MI. The knowledge of the kinetics of the curing process and the optimal amount of the curing agent for each system is of critical importance for a more efficient processing of these materials.

Preparation and Curing Behaviour of Epoxy Based Film for Moderate Temperature Prepreg

Bisphenol A epoxy resin and an acid anhydride [chosen from methyltetrahydrophthalic anhydride (Me-THPA), methylhexahydrophthalic anhydride (MHHPA) and methyl nadic anhydride (MNA)] were used to prepare epoxy films for hot melt prepreg. The effects of film composition, i.e. type and amount of epoxy resin, curing agent and curing catalyst, were investigated to develop a moderate temperature prepreg, and orthogonal experiments were used to investigate the effect of film composition on the curing behaviour of the epoxy resin film, and to determine the optimal formulation. The most favourable formulation film was cured at 100 °C for 2 h, and its curing degree was characterised by FTIR spectroscopy.