Integrated rubber (integralrubber) is a new technology product for rubber synthesis, and is also a frontier project in the field of developing macromolecular design technology. It belongs to the category of “tailor-made” (tailor-made) in polymer synthesis. It successfully applies anionic polymerization to link conformation and sequence distribution, and is particularly suitable for the preparation of butadiene homopolymeric and copolymerized integrated rubber. It is divided into the following two categories.
(1) Block homopolymers of 1,4- and 1,2-butadiene stereo segments
Its tensile stress can be more than twice that of high cis polybutadiene. Compared with low cis polybutadiene, its anti-slip performance is superior. Compared with 1,2-polybutadiene, the wear resistance is better. Due to the combination of the three, it is especially suitable for tire tread rubber.
(2) Butadiene and styrene. Block copolymer of isoprene
Such block copolymers (such as SBR-BR-SBR or SBR-IR-SBR) can exhibit more than one peak, reflecting the presence of a separate phase, thereby fully meeting the multi-performance requirements of the article.
The above two types of integrated rubber are all intelligent development achievements of polymer materials, especially the latter, which is more favored by the tire industry because it can concentrate the performance advantages of several commonly used rubber types in one body (this is also The origin of the “integration” naming).
In rubber processing, in order to balance the properties of several rubbers, a blending method is usually employed. Although this can achieve macroscopic homogeneity, it combines several characteristics, but it loses its independence. The test found that when there is only one Tg in the differential calorimetry curve of the blended rubber, there is only one peak in the dynamic viscoelastic curve. This shows that after mechanical blending, the performance of the surface has been expanded, but the advantages of each component can not be fully exerted, which limits the maximum performance of individual properties.
Integrated rubber is not the case, because it binds different microstructures in the same polymer chain, thus overcoming the weakness of blending. When two Tg appear on the calorimetric curve, it indicates participation in the integration. The segments still retain their original characteristics, so the appearance of integrated rubber expands the space for optimizing rubber properties and solves the contradiction between tread rubber properties (for example, rolling resistance and wet skid resistance often contradict) The increase in performance is not at the expense of another performance penalty.
SBR-BR-SBR is also an integrated rubber suitable for high performance tread rubber requirements. It uses butadiene, styrene as a monomer, cyclohexane as a solvent, and is initiated by a double lithium initiator to carry out negative ion polymerization to obtain a block copolymer. According to reports, under the condition of suitable synthesis conditions, the dynamic viscoelastic curve of the rubber compound has a bimodal distribution, which proves that the two-phase separation has been achieved. The resulting glue is abrasion resistant. It is resistant to wet skid and low rolling resistance and is especially suitable for tread rubber.