Effects of low molecular weight compounds with hydroxyl groups on properties of poly(L‐lactic acid)

Abstract

ABSTRACT:The effects of low molecular weight compounds with hydroxyl groups on the properties of poly(L-lactic acid) (PLLA) were investigated. The specific interaction between PLLA and 4,4Ј-thiodiphenol (TDP) was investigated by Fourier transform IR spectroscopy. The spectra of the blends suggested that there were interassociated hydrogen bonds between the PLLA chains and TDP molecules. The thermal and dynamic mechanical properties of PLLA/TDP blends were investigated by differential scanning calorimetry and dynamic mechanical thermal analysis, respectively. The results revealed that the thermal and dynamic mechanical properties of PLLA were greatly modified through blending with TDP and that PLLA/TDP blends possessed eutectic phase behavior. The effects of the thermal history on the formation of hydrogen bonds and the thermal and mechanical properties were evaluated. It was found that the properties of the blends were strongly dependent on the thermal history. In addition to TDP, PLLA blends with other low molecular weight hydroxyl compounds, including aromatic and aliphatic compounds, were also characterized. The effects of the chemical structure of the low molecular weight compounds on the properties of PLLA were discussed.

Comparative study of PHBV/TBP and PHBV/BPA blends

“…Considering the Δ H values in the first heating scans, it is surprising that the crystallinity of PHBV in TBP1, TBP3 and BPA1 is higher than that in pure PHBV (see Table 2). In contrast, for PCL/TDP, PLLA/TDP and P(3HB‐4HB)/TDP blends, it has been reported that the crystallinity of the polyester monotonously decreased by blending with dihydric phenol 10–12. A reasonable explanation for our abnormal result has not yet been found.…”

“…Wu et al have reported that this kind of additive can greatly improve the damping properties of polymer materials 7. He et al have added the dihydric phenol 4, 4′‐thiodiphenol (TDP) into a variety of synthetic and bacterial polyesters, such as poly( L ‐lactic acid) (PLLA), poly(ω‐caprolactone) (PCL), PHB, poly[(3‐hydroxybutyrate)‐ co ‐(4‐hydroxybutyrate)] [P(3HB‐ co ‐4HB)] and poly(3‐hydroxypropionate) (P3HP) 8–12. The differential scanning calorimetry (DSC) results revealed that TDP retarded crystallization of polyesters, lowered melting points ( T m s) of polyesters and led to an eutectic phenomenon in some of the blends.…”

Interfacial improvements in poly(3-hydroxybutyrate)-flax fibre composites with hydrogen bonding additives

“…1. In previous studies conducted by He et al [13][14][15], FTIR is used to monitor the peak shifts in two specific regions where the functional groups showed changes due to hydrogen bonding of the biopolyester when blended with TDP. These were further separated into its crystalline, amorphous and H-bonded components with the aid of a curve-fitting program.…”

“…There has been some literature on the studies of dihydric phenol and aliphatic polyester blends (poly (e-caprolactone) (PCL), poly(L L -lactic acid) (PLA) and PHB and its copolymers with hydroxyvalerate [12][13][14][15][16]. A suitable dihydric phenol for formation of strong hydrogen bonding is 4,4 0 -thiodiphenol (TDP) with PCL.…”

Crystallization and Thermal Behaviors of Poly(ethylene terephthalate)/Bisphenols Complexes through Melt Post-Polycondensation

“…In the case of PBT, the crystallinity and crystal size were reduced in the presence of TDP [35]. Besides, the thermal and mechanical properties of poly (L-lactic acid) PLLA and poly(3-hydroxybutyrate) [P(3HB)] were greatly influenced through blending with 4,4 -thiodiphenol (TDP) [38,39]. Despite the extensive literature published regarding the crystallization behavior of PET containing systems, very few studies have reported crystallization behaviors of PET/bisphenols complexes.…”