It’s very challenging to fabricate elastomer vitrimers that are both robust and dimensionally stable in service. Toward this issue, we initiate a multi-phase design of elastomer vitrimers by incorporating quadruple...

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Thermoplastic vulcanizates (TPVs), with a combination of excellent resilience of conventional elastomer and re-processibility of thermoplastic, have been widely explored both in academia and industry in recent years. Herein, a new type of thermoplastic vulcanizates with good mechanical performance, excellent resistance to high temperature and oil has been successfully developed based on hydrogenated acrylonitrile butadiene rubber (HNBR) and thermoplastic polyester elastomer (TPEE) by the masterbatch procedure of dynamic vulcanization. The effect of composition ratio of rubber phase/plastic phase (R/P ratio) on the mechanical properties, rheological properties, micromorphology, thermal stability, high temperature-and oil-resistance of HNBR/TPEE TPV was systematically investigated. The results show that all HNBR/TPEE TPVs exhibit good tensile strength, low hardness, superior stretchability (≥880% elongation at break) and high elasticity (only 13% residual strain when stretched at 50% strain). Interestingly, with the increase in R/P ratio, the hardness of TPVs is decreased linearly and the elasticity increases. Besides, by combining the morphology study and rubber processing analyzer suggest that size of the dispersed rubber phase domains increases significantly as R/P ratio increases, which strengthen the rubber network, creating a better elasticity but reduces the rheological properties of TPVs. In addition, the thermogravimetric analysis shows that the thermal stability of TPV improved with the increase of R/P ratio. HNBR/TPEE TPV shows excellent high temperature-and oil-resistance after aging which is expected to be used in automotive applications.

Dynamic vulcanized thermoplastic polyurethane (TPU)/methyl vinyl silicone rubber (MVQ) thermoplastic vulcanizates (TPVs) were prepared in torque rheometer. The influence of the type and amount of peroxide crosslinking agent on the mechanical properties, thermal stability, micromorphology and melt flowability was systematically investigated. The results showed that the mechanical properties of the TPVs vulcanized by 2,5-dimethyl-2,5-di (tert-butyl peroxy) hexane (DBPH) first increased and then decreased with increasing the peroxide amount, while for dicumyl peroxide (DCP) vulcanizing system the mechanical properties slowly increased. Besides, the comprehensive mechanical properties vulcanized by DBPH were better than those of DCP group. The results of the thermogravimetric analysis showed that the TPVs vulcanized by DBPH had better heat stability, corresponding to the excellent thermooxidative aging performance and the 38% increase in tensile strength after aging. In addition, the MVQ rubber particles showed better dispersing performance for DBPH vulcanizing system. The melt flow rate of the TPVs showed a linear relationship with increasing DBPH dosage and became worse after the amount of crosslinking agent exceeded 1.5 phr. By comprehensive comparison, the TPVs have better performance when use peroxide DBPH as the crosslinking agent and the dosage is 1.5 phr.

Equilibrium swelling test is employed to study the swelling responses of natural rubber (NR) in various solvents, and to determine the total Hildebrand solubility parameter (δt) of NR. The three‐dimensional solubility parameters (HSP) of NR is obtained by virtue of software package as the result of being δd = 17.50 MPa1/2, δp = 3.20 MPa1/2, δh = 1.40 MPa1/2, and δt = 17.85 MPa1/2, respectively. The swelling ratio (q) is correlated with the energy difference (Ra) in order to deeply understand the swelling principle of NR, and the results turn out that q decreased with the increase of the Ra and it can be used to explain the abnormal swelling phenomena of methyl acetate and ethyl acetate. One of the possible applications of Ra is the prediction or explanation of diffusion behaviors of small liquids in the rubber matrix. Therefore, the diffusion coefficient (D) is calculated in accordance with the Fick's law model and attempted to correlate with the Ra value. Two qualitative relationships between D and Ra and χHSP can be preliminarily established now, which can provide an easy way to predict the diffusion behavior of fluids in rubber matrix.