Towards a Supertough Thermoplastic Polyisoprene Elastomer Based on a Biomimic Strategy

Abstract

Natural rubber is one of most famous self-reinforced rubbers thanks to the phenomenon of strain-induced crystallization. It is usually used in avulcanized form to enhance the mechanical strength but this results in recycling issues.Herein at hermoplastic analogue of vulcanized natural rubber is obtained as as tructural mimic. Terminally functionalized polyisoprene rubber B-4A-PIP was prepared by using tetraanaline as physical crosslinking units.T he strong binding of tetra-analine groups gave B-4A-PIP ah igh tensile strength (15 MPa) and breaking strain of 890 %, which is muchhigher than those of undecorated copolymer B-OH-PIP.B -4A-PIP has as imilar onset strain of crystallization and crystallization index to vulcanized natural rubber.R andomly functionalized polyisoprene R-4A-PIP showed am uchl ower mechanical strength and SIC properties although R-4A-PIP and B-4A-PIP possessed similar molecular weights and amounts of tetraanaline groups.Rubbers derived from conjugated diene monomers present avast kind of commodity in the tire industry and our everyday life.A mong them, natural rubber products possess superior properties such as high tensile strength, high toughness and crack growth resistance,w hich are closely related to their terminal polar components and strain-induced crystallization (SIC) phenomena. [1][2][3] Although synthetic polyisoprene possesses similar main chain structure with natural rubber,i ts performance such as raw rubber strength, anti-fatigue and SIC properties of vulcanized form still lag behind of natural rubber. [4] Not only are the stereoregularity and molecular weights of polyisoprenes associated with their performance, but also the terminal structures. [5] Ty pically,the w-terminal of natural rubber consists of non-covalently connected proteins and a-terminal consists of phospholipids.Each polar terminal contributed to mechanical performance with specific way. [6] Inspired by this unique phenomenon found in natural rubber, one way to improve the performance of synthetic diene rubber should tune to terminal functionalization. However, this approach is rarely adopted mainly due to lack of suitable synthetic methods.A nd successful mimic of terminal struc-ture and functionality of natural rubber will deepen our understanding on high performance diene rubbers.In the meantime,r ecyclability is also very important for rubber usage.Ahuge amount of vulcanized rubbers are buried or incinerated because of inefficient recycling techniques,not only resulting in waste but also pollution. To solve this problem, malleable materials such as thermoplastic rubbers or thermosets with covalent dynamic networks [7] could be alternative options.T ypical thermoplastic rubber such as SBS does not possess the self-reinforcement properties.R ubber with ad ual-dynamic network design was made by Guo and his co-workers to achieve high mechanical performance with self-healing capability, [8] but the SIC peaks were weak even at high strain. Arecently developed vitrimer with dynamic covalent networks is still in its ...

Investigation on Synthesis and Application Performance of Elastomers with Biogenic Myrcene

“…Elastomers are vital synthetic materials in fields such as transport, industrial production, and even spaceflight and thus play a fundamental and important role in human daily activities due to their unique high soft elasticity and viscoelasticity. Thus, since the naissance of synthetic rubber, the preparation of novel high-performance soft elastomer materials has attracted the attention of scientists in both physics and chemistry. − Additionally, to date, mass elastomers have been mainly synthesized based on fossil resources, and thus, the sustainable preparation of advanced elastomers has become an important issue, particularly for synthetic rubber that is used in a wide range of applications in the automotive industry. This is due to the increasingly severe fuel consumption and environmental consequences induced by the widespread use of cars.…”

Influence of Oligopeptide Length and Distribution on Polyisoprene Properties

“…B-OH-PIP (Mn = 9.2 × 10 5 ) and R-OH-PIP (Mn = 8.2 × 10 5 ) were synthesized by the stereoselective coordination polymerization in the glove box according to our previous method [21]. The average number of hydroxyl groups in the terminal block of B-OH-PIP copolymer is approximately forty, while about one hundred hydroxyls are randomly dispersed in the rest polyisoprene chain.…”

“…For R-OH-PIP, there are about 130 hydroxyl groups randomly dispersed in the polyisoprene chain. Additionally, B-4A-PIP and R-4A-PIP are prepared according to our previous study [21]. Tetrahydrofuran was refluxed over sodium/diphenylketone under nitrogen and then distilled before use.…”

“…In our previous research of mimicking the terminal structure of natural rubber, techniques to prepare terminally oligopeptide functionalized polyisoprene have been developed [21]. However, how to tune the supramolecular binding strength of terminal structures and their principle to maintain terminal interactions need to be further explored.…”

MXene Enabling the Long-Term Superior Thermo-Oxidative Resistance for Elastomers

“…Elastomers, such as natural rubber (NR) and butadiene styrene rubber, are widely used because of their large strain reversible deformability [1][2][3][4]. In application, one of the problems with elastomers is thermo-oxidative aging, leading to the deterioration of properties and early failure.…”