Toward environment‐friendly composites of poly(ε‐caprolactone) reinforced with stereocomplex‐type poly(l‐lactide)/poly(d‐lactide)

Abstract

In this work, stereocomplex-poly(L-and D-lactide) (sc-PLA) was incorporated into poly(e-caprolactone) (PCL) to fabricate a novel biodegradable polymer composite. PCL/sc-PLA composites were prepared by solution casting at sc-PLA loadings of 5-30 wt %. Differential scanning calorimetry (DSC) and wide-angle X-ray diffraction (WAXD) demonstrated the formation of the stereocomplex in the blends. DSC and WAXD curves also indicated that the addition of sc-PLA did not alter the crystal structure of PCL. Rheology and mechanical properties of neat PCL and the PCL/sc-PLA composites were investigated in detail. Rheological measurements indicated that the composites exhibited evident solid-like response in the low frequency region as the sc-PLA loadings reached up to 20 wt %. Moreover, the long-range motion of PCL chains was highly restrained. Dynamic mechanical analysis showed that the storage modulus (E 0 ) of PCL in the composites was improved and the glass transition temperature values were hardly changed after the addition of sc-PLA. Tensile tests showed that the Young's modulus, and yield strength of the composites were enhanced by the addition of sc-PLA while the tensile strength and elongation at break were reduced.

Processing and characterization of binary poly(hydroxybutyrate) (PHB) and poly(caprolactone) (PCL) blends with improved impact properties

“…PCL is characterized by a low melting point around 60 ºC, a very low glass transition temperature, T g at about -60 ºC; nevertheless, the thermal decomposition temperature is relatively high, with values around 350 ºC [16,17]. With regard to its mechanical properties, PCL is extremely ductile with a high elongation at break value and low modulus [18,19].…”

Bioresource-based blends of poly(3-hydroxybutyrate-co-4-hydroxybutyrate) and stereocomplex polylactide with improved rheological and mechanical properties and enzymatic hydrolysis

“…22,23 Moreover, the stereocomplexes could also form in its miscible or immiscible blends in solution conditions. [24][25][26][27] More recently, Yang and coworkers succeeded in preparing stereocomplex crystallites with high crystallinity and melting temperature by a novel and interesting low-temperature approach using high-molecularweight PLA that was difficult to achieve using conventional melt blending and solution casting methods. 28,29 The results demonstrated that exclusive stereocomplex crystallites without the homocrystallites of high-molecular-weight PLA could be formed at processing temperatures as low as 160 C, either at equimolar PLLA/PDLA blends or non-equimolar PLLA/PDLA (60 : 40) blends.…”

Preparation of a novel phosphorus–nitrogen flame retardant and its effects on the flame retardancy and physical properties of polyketone

“…The flame‐retarding mechanism of PNFRs is generally divided into gas‐ and condensed‐phases . During the condensed‐phase, the thermal degradation of the flame retardant induces the generation of phosphoric acid, which promotes dehydration and liberates water during pyrolysis.…”