Effect of grafted maleic anhydride content and recyclability of dynamically cured maleated natural rubber/polypropylene blends

Abstract

Maleated natural rubbers (MNRs) were prepared using various levels of maleic anhydride (MA) at 4, 6, 8, 10, and 12 phr. Dynamically cured 60/40 MNR/PP blends with phenolic-modified polypropylene (Ph-PP) compatibilizer at a loading level of 5 wt % of PP were prepared by melt mixing process using sulfur vulcanization system. The influence of the level of MA on properties of the thermoplastic vulcanizates (TPVs) was studied. It was found that the mixing torque, apparent shear stress, shear viscosity, tensile strength, and hardness properties increased with increasing levels of the MA or grafted succinic anhydride groups in the MNR molecules. This is attributed to an increase in chemical interaction and reaction between methylol groups in the Ph-PP molecules and polar functional groups in the MNR molecules upon increasing levels of the grafted succinic anhydride groups. As a consequence, compatibilizing block copolymers of MNR and PP blocks were formed. The block copolymers were capable of compatibilizing with MNR and PP blend components via the respective blocks. Recyclability of the MNR/PP TPVs was also studied. It was found that, after processing through a number of cycles by injection molding and extrusion processing, the TPV exhibited marginal decreases in mechanical properties. This corresponded to slightly increasing size of the dispersed vulcanized rubber domains.

Cure efficiency of dodecyl succinic anhydride as a cross‐linking agent for elastomer blends based on epoxidized natural rubber

“…Epoxidized natural rubber (ENR) has been known for some time and is commercially available in three grades, respectively known as ENR10, ENR25 and ENR50, where the integer denotes the mol% of epoxide groups incorporated into the backbone of the polymer chains of natural rubber (NR) [1,2]. Epoxidation of NR can be carried out either in solution or from the latex using specific amounts of peroxy formic acid to control the degree of conversion [3][4][5] The presence of epoxy groups in the chain increases the polarity, giving rise to enhanced adhesion characteristics and oil resistance, but also to an increase in glass transition temperature up to -24 o C for ENR50 [3,4].…”

“…[2,12,13]. Pire et al [3,4] have produced self-vulcanizing rubber systems from ENR with different epoxide content using dodecanedoic acid (DDDA, a dicarboxylic acid) as curing agent.…”

“…Owing to the dual functionality of the epoxy groups in ENR, other researchers have directed studies to the development of novel self-vulcanizable blends based on mixtures of ENR with other functionalized polymers, such as carboxylated nitrile rubber and chlorosulfonated polyethylene, omitting the use of conventional vulcanizing agents. 2,10,11 Pire et al 3,4 have produced self-vulcanizing rubber systems from ENR with different epoxide content using dodecanedoic acid (DDDA, a dicarboxylic acid) as curing agent. These authors have found an enormous acceleration effect on the cure rates by the incorporation of an auxiliary agent, 1-2 dimethyl imidazole (DMI) at 2:1 molar ratio with DDDA.…”

Efficiency of high energy electrons to produce polypropylene/natural rubber‐based thermoplastic elastomer

“…Molecular level compatibility is not achieved for a PP/NR blend [24]. So, many studies have been devoted to increase the compatibility of this system [24–27]. In common practice, a third component, typically a copolymer, may be added as a compatibilizer or a chemical reaction can be induced to modify the interfacial adhesion in the two‐phase polymer blend [26].…”

Thermomechanical and Rheological Behaviours of Waste Glass Fibre-Filled Polypropylene Composites

“…There have been numerous studies on applying glass fibre to many polymers such as polyamide [2], [3], polystyrene [4], poly(ethylene terepthalate) [5], [6] , and polyolefins [7] - [9]. Some researches were focused on maleated natural rubber/polypropylene composites [10] or pristine glass fibre and polypropylene [11]. However, a few studies on the commodity polymers reinforced with waste glass fibre were reported.…”