Polyhydroxyalkanoates, a class of biodegradable polyester made by fermentation, are explored via extrusion with various additives for the goal of improving mechanical properties. Two types of PHA are used, poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) with 6% hexanoate and 8% hexanoate, to understand how copolymer ratios affect properties. The two PHAs undergo blending and reactive extrusion with additives such as radical peroxide initiator, PLA, and other synthesized polyesters, and mechanical data is obtained through tensile testing. The strain at break and aging of PHA is aimed to be improved. Lastly, analytical method development was done to optimize a gas chromatography protocol to quantify leftover peroxide initiator in the samples after reactive extrusion.