title: Effect of composition ratio on the thermal and physical properties of semicrystalline PLA/PHB-HHx composites.
abstract: In this study, composites of semicrystalline, biodegradable polylactide (PLA) and poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHB-HHx) were prepared by direct melt compounding. The physical and thermal properties of the composites were investigated as a function of the composition ratio. Differential scanning calorimetry analysis indicated that PLA and PHB-HHx formed immiscible composites over the observed range of composition. The crystallization of PLA was gradually suppressed by increasing proportions of PHB-HHx. Dynamic mechanical analysis results confirmed that the innate ductility of PHB-HHX and its inhibiting effect on PLA crystallization improved the stiffness of the composite compared to those of neat PLA. The infrared spectra of the immiscible PLA/PHB-HHx composites at two crystallization temperatures (30 °C, 130 °C) were obtained and presented. At 30 °C, PHB-HHx existed as crystalline domains in the PLA matrix, while, amorphous phase of molten PHB-HHx was diffused within the crystalline phase of PLA at 130 °C. The interaction between PHB-HHX and PLA could not be elucidated from the temperature data. Mechanical tests showed that the addition of PHB-HHx improves ductility of PLA/PHB-HHx composite. Morphological analysis revealed that small proportions of PHB-HHx exhibited less tendency to aggregate, which resulted in greater plastic deformation and improved toughness. From this study, PLA blended with small portions of PHB-HHx may further expand the use of bio-friendly resources in a variety of applications such as flexible films, food packaging and something like that.
authors.affiliation: R&D Center, LG Hausys, Ltd, 533, Hogae-1-dong, Dongan-gu, Anyang-city, Gyoungki-do, Republic of Korea. staach@dreamwiz.com
authors.forename: Jung Seop
authors.initials: JS
authors.lastname: Lim
authors.forename: Ku-il
authors.initials: KI
authors.lastname: Park
authors.forename: Gun Soo
authors.initials: GS
authors.lastname: Chung
authors.forename: Jong Hoon
authors.initials: JH
authors.lastname: Kim
mesh_terms: D020155:3-Hydroxybutyric Acid / Q000737:chemistry*; D000042:Absorption; D002152:Calorimetry, Differential Scanning; D002208:Caproates / Q000737:chemistry*; D003460:Crystallization; D018625:Microscopy, Atomic Force; D008855:Microscopy, Electron, Scanning; D011091:Polyesters / Q000737:chemistry*; D013055:Spectrophotometry, Infrared; D013314:Stress, Mechanical; D013696:Temperature; D000094122:Polyhydroxybutyrates
chemical_list: D020155:3-Hydroxybutyric Acid; D002208:Caproates; D011091:Polyesters; C115940:poly(3-hydroxybutyrate-co-3-hydroxyhexanoate); D000094122:Polyhydroxybutyrates; C033616:poly(lactide)