The usage of thermoplastic elastomers (TPEs) is increasing, and integrated hard‐soft parts can be mass produced by two‐component injection molding (or sequential molding). A key property of such parts, the adhesion between the two materials, is the topic of this study. The hard part (the first molded component) in this study was polyamide‐12 with 0 to 50 wt% glass fibers (PA12‐GF). As the second component, two TPEs were used: a vulcanized TPE and a styrenic TPE, both modified for adhesion to polyamides. The adhesion, assessed by 90° peel tests, increased with increasing melt temperatures and TPE injection rate, while it decreased with increasing glass fiber fraction in the PA12‐GF. Based on characterization of cross‐sections and fiber distributions near the interface, we propose some hypotheses for the effect of fiber fraction on the fusion between PA12‐GF and TPE. These hypotheses involve the near‐surface properties of the PA12‐GF materials, microstructure, thermo‐mechanical properties, and thermal properties. A direct effect of increasing the glass fiber fraction, that is, a reduction in adhesion as more fibers are present at the interface, does not seem to be a major effect, since few fibers are in direct contact with the TPE for any fiber fraction.

中文翻译：

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两组分注塑成型中热塑性弹性体与具有不同玻璃纤维分数的聚酰胺12之间的粘合

热塑性弹性体（TPE）的使用正在增加，并且可以通过两组分注射成型（或顺序成型）来批量生产集成的软硬零件。这种零件的关键特性是两种材料之间的粘合性，是这项研究的主题。在这项研究中，坚硬的部分（第一个模塑部件）是聚酰胺-12，玻璃纤维含量为0至50 wt％（PA12-GF）。作为第二组分，使用了两种TPE：硫化的TPE和苯乙烯的TPE，它们都经过改性以与聚酰胺粘合。通过90°剥离测试评估的附着力随着熔体温度和TPE注入速率的增加而增加，而随着PA12-GF中玻璃纤维分数的增加而降低。根据界面附近的横截面和纤维分布的特征，我们提出了一些有关纤维比例对PA12-GF和TPE融合的影响的假设。这些假设涉及PA12-GF材料的近表面性质，微观结构，热机械性质和热性质。增加玻璃纤维分数的直接效果，即随着界面处存在更多纤维而导致的粘合力降低，似乎并不是主要作用，因为对于任何纤维分数而言，很少有纤维与TPE直接接触。