Semi-IPNs formed from poly(ethylene glycol monomethyl ether acrylate) and an epoxy thermoset
✍ Scribed by Lin, Mu-Shih; Liu, Chia-Chen
- Publisher
- John Wiley and Sons
- Year
- 1999
- Tongue
- English
- Weight
- 415 KB
- Volume
- 48
- Category
- Article
- ISSN
- 0959-8103
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✦ Synopsis
Poly(ethylene glycol monomethyl ether acrylate) (PEGMEA) was synthesized from the reaction of poly(ethylene glycol monomethyl ether) (PEGME) with acryloyl chloride. Semi-IPNs based on various weight ratios of diglycidyl ether of bisphenol A (DGEBA)/PEGMEA were prepared, using isophronediamine (IPDA) and 2,2º-azo-bis(isobutyronitrile) (AIBN) as curing agents. The glass transition temperature and exothermic peak shifts were studied with diþ erential scanning calorimetry (DSC). Viscosity changes during semi-IPN formation were measured with a Brooküeld viscometer. Dynamic mechanical properties were investigated by rheometric dynamic spectroscopy (RDS).
Stress-strain curves were obtained with an Instron tensile tester, while impact resistance was measured with a computer aided falling dart impact tester.
Experimental results revealed retarded curing rates for all semi-IPNs, as evidenced from the shifts of curing exothermic peaks to higher temperatures, together with retarded viscosity increases during semi-IPN formation. These phenomena were interpreted in terms of chain entanglement between epoxy and PEGMEA. Nevertheless, the semi-IPNs indicated good compatibility as inferred from a single in DSC and a single damping peak in RDS for each semi-IPN. Improved tensile stress and T g strain along with toughness improvements were noticed for this semi-IPN system. Shear band yielding was proposed to interpret this result.