Functionalization of Liquid Natural Rubber via Oxidative Degradation of Natural Rubber

Abstract

Natural rubber (NR) is a high molecular weight natural polymer and can be degraded to liquid natural rubber (LNR) leaving certain functional groups at the end of chains. In this study, LNR samples prepared via oxidative degradation using H2O2 and NaNO2 as reagents were found to have different end groups depending on the pH of the reaction medium. In an acidic medium, LNR with hydroxyl terminal groups was formed as the degradation reaction was initiated by hydroxyl radicals produced from decomposition of peroxynitrite acid. In contrast, a redox reaction took place in an alkaline medium to yield LNR with carbonyl terminal groups. The mechanisms of reaction are discussed and proposed to explain the formation of different end groups when reaction carried out in acidic and alkaline media. Chain degradation in an acidic medium seems to be more effective than in an alkaline medium, and thus yields LNR with lower Mn.

Antibacterial Nanocomposites Based on Fe3O4–Ag Hybrid Nanoparticles and Natural Rubber-Polyethylene Blends

“…Similar results could be obtained by chemical degradation of nonvulcanized NR. By oxidative degradation of NR latex using H 2 O 2 and NaNO 2 , Ibrahim et al [26] found that the LNR had different end groups, depending on the pH of the medium. In an acidic medium, NR with hydroxyl terminal groups was formed.…”

Katalitik transfer hidrogenasi lateks karet alam dengan senyawa diimida pada skala semi pilot

“…Spektra FTIR karet terhidrogenasi dibandingkan dengan karet alam murni disajikan pada Gambar 2. Dari Gambar 2 dapat diketahui bahwa spektra FTIR karet alam dicirikan oleh adanya serapan tajam pada puncak bilangan gelombang 1662 cm -1 (ikatan rangkap tak jenuh C=C, vibrasi ulur) dan 834 cm -1 (ikatan =C-H, vibrasi tekuk) (Ibrahim et al, 2014). Puncak serapan lain yang terdapat pada rantai molekul karet alam antara lain 2960 cm -1 (ikatan CH 3 , vibrasi ulur), 1446 cm -1 (ikatan CH 3 , vibrasi tekuk), 2850 cm -1 (ikatan CH 2 , vibrasi ulur), 1375 cm -1 (ikatan CH 2 , vibrasi tekuk), dan 739 cm -1 (ikatan -(CH 2 ) 3 ) (Mahittikul et al, 2007;Mahittikul et al, 2009;Arayapranee & Rempel, 2013).…”

Characterization of different forms of vulcanized natural rubbers as elastomer spacer and toughening agent in two‐matrix filled epoxy/natural rubber/graphene nano‐platelets system

“…NR is classified as renewable and sustainable biopolymer, which is usually tapped and extracted from tropical rubber tree, known as Hevea brasiliensis. NR is extensively used in an enormous range of applications due to its high elongation, high elasticity, and resilience . Therefore, NR was used to improve the toughness properties of epoxy resins, because it is a renewable resource and is easily available in Malaysia …”