Toughening epoxy resin with blocked isocyanate containing soft chain

Lou, Chunhua; Xiao, Zhang; Wang, Yuwei; Chen, Zhaohui; Li, Hongshuang

doi:10.1002/app.41345

Cited by 12 publications

(4 citation statements)

References 24 publications

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“…Therefore, toughening of epoxies is a major challenge. Several techniques have been introduced for improving the toughness of the epoxy resins which could be divided into two main categories: physical modification (addition of a toughening agent into the epoxy resin) and chemical modification (modification in the chemical structure of the epoxy network) . Some common toughening agents are liquid elastomers, inorganic particles, and thermoplastics .…”

Section: Introductionmentioning

confidence: 99%

Systematic investigation of mechanical properties and fracture toughness of epoxy networks: Role of the polyetheramine structural parameters

Abdollahi

Salimi

Barikani

et al. 2018

J of Applied Polymer Sci

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Polyetheramine (PEA)-modified epoxies with various types of PEAs were prepared and respective effects on characteristics of epoxy networks were studied. The used PEAs were polyethylene glycol diamine (PEG-amine) and polypropylene glycol diamine (PPGamine) with two different molecular weights (i.e., 200 and 400 g mol −1 ). According to mechanical tests, the structural parameters of PEAs played an important role in final properties of epoxy/amine systems. PEG 400 -amine and PPG 200 -amine had the highest and lowest effects on the properties of epoxy networks, respectively. Whereas 10 phr PEG 400 -amine increased critical stress intensity factor (K IC ) and critical strain energy release rate (G IC ) of the epoxy up to 82 and 294%, the same number of PPG 200 -amine chains caused to increase the K IC and G IC up to 11 and 34%. This discrepancy could be assigned to higher flexibility index (φ = 26.22), longer chain length (~27 atoms), and higher secondary interactions [δ = 9.69 (cal cm −3 ) 0.5 ] of PEG 400 -amine in comparison with PPG 200 -amine [with φ = 8.08,~10 atoms in chain, and δ = 8.98 (cal cm −3 ) 0.5 ]. Shear yielding as a toughening mechanism was proposed based on microscopy of the crack tips. These in-depth studies could uncover underlying structure-property relationships in a relevant class of PEA-like modifiers, shedding light on the future design of top-performing homogeneous tough polymer networks.

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Section: Introductionmentioning

confidence: 99%

Systematic investigation of mechanical properties and fracture toughness of epoxy networks: Role of the polyetheramine structural parameters

Abdollahi

Salimi

Barikani

et al. 2018

J of Applied Polymer Sci

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“…According to literature reports, compared with free isocyanate reactants, blocked isocyanates have the advantages of lower toxicity and more environmental friendliness, and they are widely used in coating industry to reduce sensitivity to moisture and improve storage stability 37–40 . In addition, they have also been applied in the preparation of polyurethane urea insulating coatings, 41 toughening system of epoxy resin, 42 improving blending compatibility, 43 epoxy resin adhesive 44 and other fields, but there are few reports on their applications in CPU. Blocked isocyanates were formed by the reaction of isocyanates with active hydrogen atoms (oxime 45,46 , pyrazole, 47 indole, 48 phenol 49 ).…”

Section: Introductionmentioning

confidence: 99%

Application of blocked isocyanate in preparation of polyurethane(urea) elastomers

Sang

Wang

et al. 2021

J of Applied Polymer Sci

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High-performance casting polyurethane elastomers (CPUe) were successfully synthesized by the reaction of polyurethane prepolymer (PUP) blocked by methyl ethyl ketone oxime (MEKO) with diamine chain extenders. The effects of blocking agent were systematically studied on the structures, thermal stabilities, mechanical properties, and processability of polyurethane. The addition of MEKO significantly improved the tensile strength and toughness. The maximum tensile strength was 35.6 MPa, and the maximum elongation at break was 1065%. The high strength and toughness were attributed to the fact that under mild reaction conditions, the reaction tended to extend the molecular chains, which indicated that the formation of long chains was conducive to the extension and self-reinforcement of chain segments. Crystallization and strong hydrogen bonds between molecules also led to low loss factor. This deblocking polymerization strategy solves the gel problem in the polymerization process, and provides a new idea for the preparation of CPU.

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“…The E-44 cured by PEG-MI-b-TDI was toughened without sacrificing the tensile shear strength. 14 On the other hand, recently, considerably attention has been paid to prepare novel polymers from renewable resources to replace petroleum-based products in response to fossil fuel depletion and the need for environmental protection. 15 Vegetable oils may offer an ideal alternative to chemical feedstocks.…”

Section: Introductionmentioning

confidence: 99%

“…Lou synthesized a series of imidazole (MI)-blocked 2,4-toluene diisocyanate (TDI) with polyethylene glycol (PEG-400) as the soft segment (PEG-MI- b -TDI) for toughening and curing the bisphenol A type epoxy resin (E-44). The E-44 cured by PEG-MI- b -TDI was toughened without sacrificing the tensile shear strength …”

Section: Introductionmentioning

confidence: 99%

Preparation and Properties of Polyether Aliphatic Polymerized Amide as a Vegetable Oil-Based Epoxy Curing Agent

Jing

Xia

et al. 2019

ACS Omega

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An epoxy curing agent polyether aliphatic polymerized amide (PEAPA) was synthesized using epoxy fatty acid methyl ester and diethylenetriamine. The Fourier transform infrared spectra and 1 H NMR analysis indicated successful synthesis of PEAPA. Gel permeation chromatography showed a high degree of polymerization. The obtained PEAPA was used to cure E51 epoxy resin and partially replace rigid 1,3-cyclohexanediamine curing agent. A series of epoxy resins with varying rigidities were prepared. The mechanical and thermal properties of the materials were analyzed. Mechanical property tests showed that the tensile strength and hardness of the materials decreased gradually with increased PEAPA content. However, elongation at breaks of the prepared materials increased with increased PEAPA content. Micromorphological investigation indicated excellent compatibility between PEAPA and the curing system. Furthermore, a dynamic mechanical thermal analysis demonstrated that the glass transition temperature of the epoxy resin decreased with increased PEAPA content. Thermal stability, while still excellent, decreased slightly with the addition of PEAPA. At the primary weight loss stage, initial decomposition temperatures for all resins were above 330 °C.

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Toughening epoxy resin with blocked isocyanate containing soft chain

Cited by 12 publications

References 24 publications

Systematic investigation of mechanical properties and fracture toughness of epoxy networks: Role of the polyetheramine structural parameters

Systematic investigation of mechanical properties and fracture toughness of epoxy networks: Role of the polyetheramine structural parameters

Application of blocked isocyanate in preparation of polyurethane(urea) elastomers

Preparation and Properties of Polyether Aliphatic Polymerized Amide as a Vegetable Oil-Based Epoxy Curing Agent

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