Toughening of epoxy systems by brominated epoxy

This paper describes the experimental findings of the study of a series of PU/epoxy composites, which formed interpenetrating networks and have shape‐memory properties. The morphological variation for different chemical compositions and the influences of morphology on mechanical performance and shape‐memory behavior are discussed. Length and mass fraction of polyethylene glycol (PEG) units are chosen as the key parameters in this study. The molecular weight of PEG was varied from 400 (as such PEG units are unable to crystallize) to 1500, 4000, and 6000, which are crystallizable. It was shown that the crystallization of PEG units is the key parameter, which determines the mechanical performance and shape‐memory behavior of PU/epoxy composites in this study. DMTA results show the linear dependence of glass transition temperature and tensile strength, elongation, and other mechanical parameters on the amount of PEG in PU/epoxy composites independently of the amount of PEG unit lengths. The maximal value of shape fixation rate was achieved for 30–40 mass percentage of PEG 4000 (4.5 × 10−2 s−1 at Tg + 20°C) or PEG 6000(4.1 × 10−2 s−1 at Tg + 20°C) in PU/epoxy composites.

Section: Resultsmentioning

confidence: 99%

The effect molecular weight of polyol components on shape memory effect of epoxy‐polyurethane composites

Bratasyuk

Zuev

2021

“…Epoxy resin is the most important matrix in fiber reinforced resin matrix composites because of its excellent mechanical and molding process properties. [1][2][3][4][5] The types and applications of epoxy resin are becoming more and more extensive. [6,7] Various types of new high-performance epoxy resin have also produced to satisfy the requirements of national defense, aerospace and other special fields.…”

Section: Introductionmentioning

confidence: 99%

Tetraglycidyl ether 1.1.2.2‐tetraphenyl ethane epoxy resin modified by carbon nanotubes

Zhou

Lei

2022

Usually, the reinforcing effect of carbon nanotubes (CNTs) in a polymer is related to the properties of the matrix and its dispersion in the matrix. In this paper, the modification effect of CNTs on high performance tetraglycidyl ether 1.1.2.2-tetraphenyl ethane epoxy resin (TGETPE) was studied. CNTs grafted with amino groups (N-CNTs) were used to react with DGEBA to form a well dispersed CNTs / epoxy resin mixture (E-CNTs), and then E-CNTs were added to TGETPE/methyl tetrahydrophthalic anhydride (MeTHPA) to form a E-CNTs-reinforced TGETPE composites. The effect of different content of E-CNTs on TGETPE/MeTHPA cured resin was studied. With an increase in content of E-CNTs, the mechanical properties of the cured sample first increase and then decrease. At E-CNT contents of 0.4 and 0.6 wt%, the tensile strength and bending strength of the composites increased by 39% and 34%, respectively. Young's modulus of the cured composite increases with the addition of E-CNTs. In addition, the addition of E-CNTs can improve the thermal properties of the cured sample.

“…Epoxy resin (EP) is a widely used and indispensable thermosetting plastic for modern industry because of its excellent moldability, thermal, mechanical, anti-corrosion, and chemical resistant properties. [1][2][3] However, as a brittle polymer with three dimensions crosslinked structure inside, it lacks self-lubricating properties for being used in friction and wears protection. [4][5][6] To improve the lubricating and anti-wear properties of traditional epoxy resin, researchers have made great efforts, such as mixing lubricating secondary polymer (polytetrafluoroethylene (PTFE), [7,8] rubber, [9] polyurethane (PU) [10] ), incorporating anti-wear fillers (fibers [11][12][13] and inorganic particles [14,15] ) and doping nanofillers (nanosheets, [6,16,17] nanotubes [18,19] and nanoparticles [5,20] ) with both functions.…”

Section: Introductionmentioning

confidence: 99%

Improved tribological performance of epoxy composites containing core–shell PE wax@SiO₂ nanoparticles

Zhao

Wang

et al. 2022

The poor tribological performance of epoxy limits its application in the field of lubrication and wear protection, but there is still great potential for improvement. In this paper, polyethylene wax contained by silica core–shell particles was prepared and incorporated into the epoxy resin. The effects of particle content, normal load, and reciprocating linear velocity on the friction and wear properties of epoxy‐based composites were investigated. Due to the lubricating and anti‐wear effect of core–shell particles, the 10 wt.% amount can reduce at most the friction coefficient and wear rate of epoxy by 57% and 94%, respectively. The inflatable and burst core–shell particles, transfer film, and corrosion were observed on the worn surface. A mechanism referring to fracture, the release of lubricating core, and transfer film formed by a mixture of core and shell materials were deduced to explain the enhancement effect of core–shell particles in the epoxy matrix. That also suggests that the polyethylene wax@silica core–shell particles will be a potential lubricating and wear‐resistant additive of epoxy.