Functionalized liquid natural rubber and liquid epoxidized natural rubber: A promising green toughening agent for polyester

Abstract

Toughened unsaturated polyester resins (UPRs) were prepared using two different reactive rubbers, namely, liquid natural rubber (LNR) and liquid epoxidized natural rubber (LENR). The effect of varying amounts of LNR and LENR on the morphology, thermal, and mechanical properties of UPR were evaluated. Fourier Transform Infrared spectroscopy was used to investigate the probable crosslinking reaction and changes in the functional groups on crosslinking. Field emission scanning electron microscopy and infinite focus microscopy were used to study the morphology of fracture surfaces. Tensile test showed that both the rubber-modified resins (1.5 wt %) improved tensile strength. The viscoelastic properties and thermal stability of the toughened polyesters were evaluated using dynamic mechanical thermal analysis and thermogravimetric analysis, respectively. A slight reduction in the glass transition temperature (T g ) of the polyester was reported on the addition of both the rubbers. An increment in impact strength and fracture toughness was observed at 1.5 wt % for LNR and 4.5 wt % for LENR-modified UPR. The results showed that both the liquid rubbers improved the mechanical properties of UPR. However, LENR-modified UPR exhibited a more significant improvement in the mechanical properties compared to LNR-modified UPR.

Cellulose nanocrystal reinforced liquid natural rubber toughened unsaturated polyester: Effects of filler content and surface treatment on its morphological, thermal, mechanical, and viscoelastic properties

“…However, the incorporation of rubber particles into composites as a toughening agent can sometimes have undesirable effects such as lowering the glass transition temperature (T g ) and the tensile properties (particularly, strength and modulus) of the material [2,3].…”

“…The most frequently used and widely accepted method to improve the toughness of thermoset resin is to add reactive liquid rubbers [2]. However, the incorporation of rubber particles into composites as a toughening agent can sometimes have undesirable effects such as lowering the glass transition temperature (T g ) and the tensile properties (particularly, strength and modulus) of the material [2,3].…”

Pengoptimuman Tindak Balas Penghidrogenan Getah Asli Cecair melalui Kaedah Rangsangan Permukaan

“…Modifikasi NR kepada LNR menghasilkan NR yang mempunyai rantai polimer yang lebih pendek dan berat molekul yang lebih rendah (M w <10 5 ) tidak mengubah struktur utama rantai poliisoprena. Proses modifikasi NR kepada LNR boleh dilakukan melalui kaedah redoks (Phinyocheep & Duangthong 2000), pengoksidaan terma (Kargarzadeh et al 2014), ozonolisis (Kodama et al 2003) dan pengoksidaan fotopemeka (Ibrahim 1994).…”

“…LNR disediakan menggunakan kaedah fotodegradasi (Kargarzadeh et al 2014). Sebanyak 1 kg NR direndam dalam pelarut toluena sehingga mengembang.…”

Morphological Studies in Novel Liquid Rubber Modified Epoxies

“…In addition to shear yielding, other mechanisms viz. micro-cracking, crack deflection, crack bifurcation, crack pinning, crack bridging, or multiple fracture may also exist in the rubber-epoxy blends [3]. Numerous efforts have been made to blend a host of liquid rubbers with commercially available DGEBA based epoxy resins to enhance the toughness of the epoxies.…”