Thermal and mechanical properties of plasticized poly(L‐lactic acid)

Abstract

Acetyl tri-n-butyl citrate (ATBC) and poly-(ethyleneglycol)s (PEGs) with different molecular weights (from 400 to 10000) were used in this study to plasticize poly(L-lactic acid) (PLA). The thermal and mechanical properties of the plasticized polymer are reported. Both ATBC and PEG are effective in lowering the glass transition (T g ) of PLA up to a given concentration, where the plasticizer reaches its solubility limit in the polymer (50 wt % in the case of ATBC; 15-30 wt %, depending on molecular weight, in the case of PEG). The range of applicability of PEGs as PLA plasticizers is given in terms of PEG molecular weight and concentration. The mechanical properties of plasticized PLA change with increasing plasticizer concentration. In all PLA/plasticizer systems investigated, when the blend T g approaches room temperature, a stepwise change in the mechanical properties of the system is observed. The elongation at break drastically increases, whereas tensile strength and modulus decrease. This behavior occurs at a plasticizer concentration that depends on the T g -depressing efficiency of the plasticizer.

Infrared and Raman studies on polylactide acid and polyethylene glycol-400 blend

“…As a plasticizer, polyethylene glycol (PEG) is a suitable plasticizer agent because its hydrophilic group interacts with the hydrophobic group on PLA, as shown in Fig 1.Solubility and miscibility of PEG will decrease with increasing molecular weight [10]. Addition of low molecular PEG is most suitable to improve miscibility [11] and create homogenous blended and even matrix of PLA [7,12].…”

“…However, if the amount of PEG exceeds a specific limit, a basic problem in polymer blends is created. In addition, PEG exhibits phase separation with PLA when its concentration is above 10% [10].…”

Thermal Properties, Crystallinity, and Oxygen Permeability of Na-montmorillonite Reinforced Plasticized Poly(lactic acid) Film

“…Surprisingly, PEG has a good miscibility with PLA and does not show phase separation [4]. On the other hand, solubility and miscibility of PEG will decrease with increasing molecular weight [5]. Introducing PEG400 at about 5% into PLA created good barrier properties and a morphological structure, although it reduced the thermal properties of plasticized PLA film [6].…”

Synthesis of branched poly(lactic acid) bearing a castor oil core and its plasticization effect on poly(lactic acid)

“…Various compounds have thus far been used to achieve good plasticization effects in PLLA. These include citrates, poly(ethylene glycol), bis(2-ethylhexyl) adipate, glyceryl triacetate, triacetin, oligomeric poly(1,3-butylene glycol adipate), diethyl bishydroxymethyl malonate, oligomers of citrate and poly(propylene glycol) [21][22][23][24][25][26][27] The plasticization of PLLA by these compounds often resulted in a substantial decrease in the crystallinity of PLLA, which causes a lowering of heat resistance and tensile strength. 25 In some plasticizers with low-molecular weight, the plasticization effect became lower over time because of the migration or volatilization of the plasticizer.…”