Mechanical Properties of Bioepoxy Polymers, Their Blends, and Composites

Al-Maharma, Ahmad Y.; Heider, Yousef; Markert, Bernd; Stoffel, Marcus

doi:10.1002/9783527823604.ch7

Cited by 4 publications

(1 citation statement)

References 146 publications

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“…The flexural modulus at above 3 GPa for the TA-32 to TA-66 systems compares well with other structural fossil fuel-derived networks such as the work of Qi et al, Gan et al, and Lee et al who all reported values above 3 GPa. The flexural strength for TA-53 and TA-79, the samples with the highest strength at a maximum of around 50 MPa, are certainly lower than many high-performance networks but still compares favorably to many other epoxy polymer networks. − The trends reported here support the results presented thus far, wherein the TA-53 composition appears to represent the optimum stoichiometry balancing mechanical and thermal properties. Also, that increased heterogeneity of the network and reduced T g indicated by DMTA would be expected to reduce modulus.…”

Section: Results and Discussionsupporting

confidence: 74%

Impact of Stoichiometry on the Network Structure, Properties, and Processing Relationships of an Epoxy Tannic Acid Resin System

Senanayake,

Gan,

Zhang

et al. 2024

ACS Appl. Polym. Mater.

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In this work, diglycidyl ether of bisphenol A (DGEBA) is cured with the bioderived branched polyphenol tannic acid (TA) to establish the optimum composition for enhanced mechanical and thermal properties and processability. To do this, the composition of DGEBA to TA is systematically varied and the impact upon the cure kinetics, network structure, and mechanical and thermal properties is determined. As the concentration of TA increases, the mechanical and thermal properties exhibit a peak in performance corresponding to the formation of a homogeneous microstructure where the cure reaction occurs initially via the faster epoxide TA addition and then by the slower homopolymerization of the epoxy resin. Although the precise stoichiometry of the optimum formulation is unknown, given the uncertainty surrounding the reactivity of each phenolic group, this partially bioderived resin system displays properties and processability consistent with other highly aromatic and highly cross-linked fossil fuel-derived resin systems. For example, the maximum T g , determined by DMTA, is 190 °C (tan δ max), the flexural modulus is over 3 GPa, the flexural strength approaches 50 MPa, and the fracture toughness K IC is 0.6 MPa m 1/2 . Furthermore, the maximum T 5% decomposition temperature of the fully cured network is 361 °C, while the char yield is 23.9%, which is entirely consistent with the degradation properties of high-performance epoxy networks. The detailed structure−property relationships presented here are an important step in the commercial exploitation of bioderived resin systems.

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