Plasticizing effect of poly(ethylene glycol)s with different molecular weights in poly(lactic acid)/starch blends

Abstract

Binary and ternary blends composed of poly(lactic acid) (PLA), starch, and poly(ethylene glycols) (PEGs) with different molecular weights (weight-average molecular weights 5 300, 2000, 4000, 6000, and 10, 000 g/mol) were prepared, and the plasticizing effect and miscibility of PEGs in poly(lactic acid)/starch (PTPS) or PLA were intensively studied. The results indicate that the PEGs were effective plasticizers for the PTPS blends. The small-molecule plasticizers of PEG300 (i.e., the M w of PEG was 300g/mol) and glycerol presented better plasticizing effects, whereas its migration and limited miscibility resulted in significant decreases in the water resistance and elongation at break. PEG2000, with a moderate molecular weight, was partially miscible in sample PTPS3; this led to better performance in water resistance and mechanical properties. For higher molecular weight PEG, its plasticization for both starch and PLA was depressed, and visible phase separation also occurred, especially for PTPS6. It was also found that the presence of PEG significantly decreased the glass-transition temperature and accelerated the crystallization of the PLA matrix, depending on the PEG molecular weight and concentration.

Processing and characterization of high environmental efficiency composites based on PLA and hazelnut shell flour (HSF) with biobased plasticizers derived from epoxidized linseed oil (ELO)

“…During the cold crystallization process, both density and stiffness increase to the highly packed structure [16,28]. Once the crystallization process is completed, the evolution of the storage modulus (G') follows similar tendency as observed in the initial stages with maximum values for unmodified composites and decreasing values with higher ELO content.…”

“…), oligomeric and polymeric plasticizers such as commercial adipates (DOA -(bis(2-ethylhexyl) adipate), lactic-acid derived polymers, poly(ethylene glycol), poly(propylene glycol), etc. [8,[22][23][24][25][26][27][28][29].…”

Poly(lactic acid) formulations with improved toughness by physical blending with thermoplastic starch

“…29,35 The change in the glass transition temperature (T g ) is more clearly detectable by analyzing the evolution of the damping factor (tan d) with temperature ( Figure 6). During the cold crystallization, amorphous domains in PLA tend to rearrange in a packed structure to form crystalline zones that contribute to increase its mechanical resistance and rigidity (almost twofold higher regarding the minimum values achieved after the glass transition relaxation).…”

Plasticizing effect of biobased epoxidized fatty acid esters on mechanical and thermal properties of poly(lactic acid)

“…which can lead to tailored properties in terms of mechanical response, biodegradation rate, etc. Another interesting approach is the use of environmentally friendly and non-toxic plasticizers such as poly(ethylene glycol), PEG [16][17][18], poly(propylene glycol), PPG [19], oligomeric lactic acid, OLA [20], citrates such as acetyl tributyl citrate (ATBC) [21][22][23] or tributyl citrate (TBC) [22,[24][25][26].…”