Mechanical and Thermal Properties of Unsaturated Polyester/Vinyl Ester Blends Cured at Room Temperature

Abstract

Influence of weathering effect in natural environment on thermal properties hybrid kenaf blast/glass fibre and unsaturated polyester composite M Mohammed, A R Rozyanty, B O Beta et al. (10, 20, 30, 40,and 80 wt.%) using mechanical blending method. The blends were cured at room temperature using methyl ethyl ketone peroxide (MEKP) (4 wt.%) as catalyst initiator without the presence of catalystaccelerator. The effect of vinyl ester composition on theenhancement of mechanical and thermal properties of unsaturated polyester/vinyl ester blends was investigated.The polymer blends were characterized by Fourier Transform Infra Red (FTIR)spectroscopy, tensile testing, hardness testing, scanning electron microscopy (SEM) and thermogravimetric analysis (TGA). IR spectra showed UP and VE peaks. The curing copolymerization reactionoccurred at vinyl (C=C) bonds. The addition of vinyl esters enhanced mechanical and thermal properties. The UP/VE blends showed homogeneous morphology, transparent and copolymer thermoset blend.Keywords: unsaturated polyester, vinyl ester, polymer blend, thermal properties IntroductionUnsaturated polyester is a widely used thermosetting resin. Unsaturated polyester has a reactive vinyl (carbon-carbon double) bond. Styrene is added to unsaturated polyester as asolvent and acrosslinking agent for curing reaction. The organic peroxide is used to initiatethe reaction. Organic salt isadded to accelerate the reaction. The polymer is achieved as a result of random condensation copolymerization reaction between styrene and unsaturated vinyl double bonds by free radical mechanismforming crosslinked network structure [1,2]. Unsaturated polyester is a resin (prepolymer) with low price, light weight, easy processing and water resistance. Unsaturated polyester commonly used in laminating resin, composites, coating, adhesive, microelectronic, aerospace, building, automotive, and shipbuilding. However, unsaturated polyester shows limited mechanical and thermal properties. It is necessary to enhance the properties of unsaturated polyester.The properties of unsaturated polyester have been enhanced by theadditionof carbon fiber , fly ash, carbon nanotube, and polyamide [3][4][5][6]. Vinyl ester is an attractivehigh-performance thermoset polymer. Vinylester has reactive double bonds with rigid epoxy structure. Vinyl ester is synthesized by the reaction of epoxy with methacrylic

Vitrimerization of Crosslinked Unsaturated Polyester Resins: A Mechanochemical Approach to Recycle and Reprocess Thermosets

“…The existence of hydroxyl groups in the UPR network has been reported in the literature. [37][38][39] However, it is crucial to investigate the effect of catalyst and alcohol on the efficacy of the transesterification exchange reaction to enable applying the process to a wide range of polyester thermosets with different formulations and degrees of crosslinking. By adding the catalyst and alcohol, the peaks related to carboxylate-zinc vibrations appear in the spectrum (1560−1520 cm −1 ) and intensity of the peaks corresponding to hydroxyl groups a) The sample V-3 is prepared with the same amount of catalyst as sample V-1.…”

Pultruded GFRP Reinforcing Bars Using Nanomodified Vinyl Ester

“…In the FTIR spectroscopy shown in Figure 8 , a chemical reaction in FTIR spectral analyses can be identified by observing the shift in vibration peaks. Typical bands of vinyl ester were found at 3415 for the OH hydroxyl group, 3059 for the CH aromatic benzene ring, 2963 for the CH aliphatic, 1507 cm −1 for the CH aromatic benzene ring, 1232 cm −1 for the C–O ester, 1180 cm −1 for the C=O ether, and 696 cm −1 for the CH monosubstituted aromatic benzene ring [ 52 ]. In COOH-MWCNTs, there are normally three distinctive bands, which are C=O, O–H, and C–O [ 53 ].…”

“…The FTIR spectrographs confirmed the hypothesis that COOH-MWCNTs had chemical effects on the vinyl ester and, thus, resulted in an improved interaction with the glass fibers used in the pultrusion of GFRP reinforcing bars. The chemical structure of vinyl ester resin after initiation and cross-linking with a styrene monomer and its reaction with the silane sizing agent on the surface of glass fiber is shown schematically in Figure 13 a [ 52 , 64 , 65 ]. The COOH functionalization group of the MWCNTs had a chemical reaction with the vinyl ester on one side and with the silane sizing of the glass fibers on the other side ( Figure 13 b).…”

“… Chemical interactions in ( a ) neat pultruded GFRP bars [ 52 , 64 , 65 ], and ( b ) pultruded GFRP bars incorporating 0.5 wt.% COOH-MWCNTs. Relationship with the surface morphology of ( c ) broom failure in neat pultruded GFRP bars and ( d ) absence of broom failure in pultruded GFRP incorporating 0.5 wt.% COOH-MWCNTs.…”

On the toughening of unsaturated polyester resins using nadimide end‐functionalized polyether telechelics

“…Ardhyananta et al [10] studied the vinyl ester blends of UPER and found the property enhancement on blending. Abrala et al [11] developed an effective tough UPE blend by using vinyl ester (VE) and methyl methacrylate (MMA).…”