Disclosed herein are high performance semi-aromatic polyamide compounds having improved performance indicators for various applications, including alkaline battery end cap seal assembly applications. In one preferred embodiment, the disclosure relates to compounds comprising a semi-aromatic polyamide component comprising recurring terephthalamide and/or isophthalamide units, an impact modifier component comprising a modified polyolefin elastomer, one or more synergistic blends of sterically hindered phenolic stabilizers and phosphonates and one or more relatively high molecular weight organic phosphite stabilizers, and a fine talc nucleating agent.