EMA-GMA, POE-GMA and EBA-GMA are currently available on the market for efficient PBT toughening agents.
The molecular chain of EMA-GMA and EBA-GMA has ester groups, while POE-GM molecular chains are saturated bonds. Theoretically, the thermal stability of saturated carbon chains is better than that of unsaturated carbon chains. POE and EMA raw materials of the oxidation induction time also proved this point. However, the oxidation-induced temperature test for the toughener product also showed that SOG-02 (POE-GMA) had better thermal stability than EMA-GMA and EBA-GMA in air.
Second, from the molecular backbone flexibility, POE-GMA> EBA-GMA> EMA-GMA. The lower the glass transition temperature Tg, the better the flexibility of the molecular chain, the better the toughening effect. Therefore, only from the molecular structure and Tg to consider, POE should be a suitable matrix of toughening agent is an appropriate choice.
PBT notched impact strength is very low, limiting its application, the industry's most important toughening method is to join the functionalized elastomer toughening. However, PBT toughening modified, will cause a decline in mobility. Because of the addition of reactive groups (such as GMA) after the toughening agent, on the one hand the introduction of olefins part of the long chain of PBT molecules on the tangled role, on the other hand in situ formation of PBT-GMA-elastomeric copolymer, that is, Which is equivalent to increase the PBT molecular weight, resulting in increased viscosity of the blend, making the toughening of PBT significantly reduced mobility. In order to meet the requirements of thin-walled, multi-cavity and so on, PBT should be toughened by selecting a toughening agent with little effect on the flowability without affecting the toughening effect.