Characteristics of Biodegradable Polylactide/Thermoplastic Starch/Nanosilica Composites: Effects of Plasticizer and Nanosilica Functionality

The present research aims to improve the compatibility between relatively hydrophobic poly(lactic acid) (PLA) and hydrophilic thermoplastic starch (TPS) and the properties of the PLA/TPS blends by replacing TPS from native cassava starch (TPSN) with TPS from acetylated starch (TPSA). The effects of the degree of acetylation (DA) of acetylated starch, that is, 0.021, 0.031, and 0.074, on the morphological characteristics and properties of PLA/TPS blend are investigated. The melt blends of PLA and TPS with a weight proportion of PLA:TPS of 50:50 are fabricated and then blown into films. Scanning electron microscopy confirms the dispersion of TPS phase in the PLA matrix. Better dispersion and smaller size of the TPS phase are observed for the PLA/TPSA blend films with low DA of acetylated starch, resulting in improved tensile and barrier properties and increased storage modulus, thermal stability, and Tg, Tcc, and Tm of PLA. Elongation at break of the PLA/TPSA blend increases up to 57%, whereas its water vapor permeability and oxygen permeability decrease about 15%. The obtained PLA/TPSA blend films have the potential to be applied as biodegradable flexible packaging.

Section: Resultssupporting

confidence: 90%

Compatibility improvement of poly(lactic acid)/thermoplastic starch blown films using acetylated starch

Noivoil

Yoksan

2020

“…The decrease in the modulus after application of the SNP in the polymer matrix has also been reported in other studies 18,41 . Furthermore, the storage modulus in the glassy region is higher for the SLPUF1 than the SLPUF0.5 and SLPUF0.1 samples, which is due to the stiffness of solid nanoparticles 45 46 …”

Section: Resultssupporting

confidence: 81%

Evaluation of microstructure, thermal, and mechanical properties of the green lignin‐based polyurethane/hydrophobic silica nanocomposite foam

Mohammadpour

Sadeghi

2020

In the present study, lignin‐based polyurethane foam (LPUF) and hydrophobic silica LPUF (SLPUF) were synthesized using different concentrations of silica nanoparticles (SNP). The effect of SNP on the structure and properties of SLPUF samples was investigated and compared with LPUF through the scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT‐IR), thermogravimetric analysis (TGA), dynamic mechanical thermal analysis (DMTA), and compressive tests. The FT‐IR results showed changes in the H bonding interactions between the structures of SLPUF samples. Moreover, the SEM results indicated a decrease in the cell size of SLPUF samples. Incorporation of SNP improved the thermal stability of SLPUF samples while the compressive strength of SLPUF samples decreased in comparison with LPUF. Furthermore, the DMTA results revealed a decrease in the glass transition temperature from 90°C (LPUF) to around 52°C (SLPUF samples). This means that applying the hydrophobic SNP changes the foam type from a rigid foam to soft one. Therefore, significant changes were observed in the physical–chemical properties of the SLPUF samples compared to the LPUF.

“…The addition of RH with an irregular shape may interfere with the crystallization process of the PLA, creating difficulty in chain rearrangement and disrupting the intermolecular attraction between the PLA chains themselves. Moreover, the chain mobility of PLA has been increased, owing to the plasticizing effect of GLY plasticizer 44 . This is corresponded with the increased impact strength, as discussed in the previous section.…”

Section: Resultsmentioning

confidence: 53%

Enhanced biodegradation and processability of biodegradable package from poly(lactic acid)/poly(butylene succinate)/rice‐husk green composites

Sirichalarmkul

Kaewpirom

2021

This work aims to study the possibility to process PLA/PBS/RH green composites into hexagonal plant‐pots employing a large‐scale industrial operation using injection molding. Green composites based on poly(lactic acid) (PLA), poly(butylene succinate) (PBS), and rice husk (RH) with various RH contents (10–30%wt.) were produced successfully using a twin‐screw extruder. The compatibility of RH‐matrix was improved by chemical surface modifications using a coupling agent. RH was analyzed as an effective filler for PLA to develop green composites with low cost, high biodegradability, improved processability, and comparable mechanical properties as unfilled PLA. With increasing RH content, tensile modulus of the composites increased gradually. The addition of PBS, at PLA/PBS ratio of 60/40, improved the elongation at break and impact strength of PLARH30 by 55% and 7.1%, respectively. The suitable processing temperatures for PLA decreased from 220–230°C to 170–180°C when 30%wt. RH was composited into PLA matrix and were further reduced when PBS was applied. After biodegradation via either enzymatic degradation or hydrolysis, surface erosion with a large number of voids, mass loss, and the substantial decrease in tensile strength of all the composites were observed. In addition, the biodegradation of the composites has been improved by the addition of either RH or PBS.