Toward partially bio-based thermoplastic vulcanizates based on poly (lactic acid) and chloroprene rubber

Polylactic acid (PLA)-based thermoplastic vulcanizates (TPVs) were fabricated using dynamic and static vulcanization in the presence of untreated and surface-treated zinc oxide (ZnO). Initially, the effect of chloroprene rubber (CR) as the elastomeric phase in the PLA-based thermoplastic elastomer (TPE) was tailored. The CR content varied from 20 to 40 wt%, leading to 46%–70% and 19%–76% decrement in tensile strength and modulus, respectively, while elongation at break increased up to 9–13 times, highlighting the soft rubber phase's impact on ductility. Impact resistance testing showed improved toughness with CR addition, peaking at 20 wt% CR. Scanning electron microscopy (SEM) revealed matrix-dispersed morphology with increasing CR droplet size, and co-continuous morphology at 40 wt% rubber in BP6R4. In the next step, the optimized TPE was selected, and the focus shifted to investigate the effect of dynamic/static vulcanization on mechanical properties. It is revealed that adding modified ZnO (ZnO60) increased melt torque, but it decreased after 1.5 min. All vulcanized samples exhibited lower tensile strength and elongation at break but higher elastic modulus due to metallic particle reinforcement. ZnO particle agglomerates and rubber aggregations led to lower mechanical properties. These findings offer quantitative insights into vulcanization's influence on PLA-based TPVs, informing partially biobased TPEs development and addressing vulcanization limitations. Highlights: Fabrication of biobased thermoplastic elastomer (TPE) and thermoplastic vulcanizate (TPV) based on polylactic acid/chloroprene rubber (PLA/CR) shows the sustainable material prospect. The effects of dynamic/static vulcanization on TPE's behavior are investigated. Micro-morphology analysis showed dispersed CR phase in TPEs when PLA content is <40 wt%. The addition of modified ZnO through static vulcanization minimized degradation. ZnO Agglomeration and CR aggregations caused subpar TPV mechanical properties.