Injection foam molding of poly lactic acid (PLA) blended with poly hydroxy alkanoate (PHA) to improve impact properties

宏控工程技术公司在开发创新塑料方面做出了非凡的努力 用于为各种用途的商业化聚合物发泡的加工设备。宏想要 开发经济实惠的材料配方和泡沫注射成型工艺，可生产高密度 具有优异机械性能和泡孔结构的聚乳酸泡沫塑料产品。解放军是一种基于生物的， 可生物降解和环境友好的热塑性聚合物，具有巨大的潜力 应用领域如汽车零部件、医疗器械、建筑、包装等。然而，解放军已经 熔体强度低、脆性高等固有缺陷。为了获得高熔体强度 足够获得更精细和更封闭的泡孔，我们将尝试添加聚四氟乙烯纤维，这些纤维是 有望增加聚乳酸分子链缠结的数量。作为一种试图增加 聚乳酸泡沫塑料的延展性，将PHA与聚乳酸共混。聚羟基烷酸酯(PHA)是更理想的 与聚乳酸共混，增强材料的韧性和延展性。关于添加的抗冲击改性剂的含量，它 需要最小化到略微满足以下力学性能要求的水平 每种应用，因为这些聚合物比聚乳酸贵得多。为了达到卓越的成绩 泡沫塑料制品采用泡沫塑料注射成型工艺，泡沫塑料的加工条件和参数应 也要进行优化。由于聚乳酸是一种半结晶聚合物，发泡的加工窗口基本上是 非常狭窄，这使得聚乳酸的发泡更具挑战性。因此，一种经济上可行的材料 配方和注射发泡参数将通过系统计划的泡沫实验来开发 使用泡沫注塑机。

Macro Engineering and Technology Inc. has been making remarkable efforts to develop innovative plastic processing equipment for foaming the commercialized polymers for diversified applications. Macro would like to develop an affordable material recipe and foam injection molding process which can produce high-density PLA foam products with excellent mechanical properties and a cellular structure. PLA is a bio-based, biodegradable and environmentally friendly thermoplastic polymer which has a huge potential for a variety of applications such as automotive parts, medical devices, construction, packaging, and so on. However, PLA has a couple of intrinsic drawbacks of low melt strength and high brittleness. In order to achieve high melt strength enough to obtain finer and more closed cells, we will try to add polytetrafluoroethylene fibers which are expected to increase the number of molecular chain entanglement of PLA. As an attempt to increase the ductility of PLA foam, PHA will be blended with PLA. Poly hydroxy alkanoate (PHA) is more desirable to be blended with PLA to enhance the toughness and ductility. Regarding the content of added impact modifiers, it needs to be minimized to the level of marginally satisfying the requirement of the mechanical properties in each application, because these polymers are much more expensive than PLA. In a bid to achieve excellent foam products using a foam injection molding process, the foam processing conditions and parameters should be optimized as well. Since PLA is a semi-crystalline polymer, basically the processing window for foaming is very narrow, which makes foaming of PLA more challenging. Therefore, an economically viable material recipe and injection foaming parameters will be developed through systematically planned foam experiments using a foam injection molding machine.