Synthesis of Poly(D-Lactic Acid) Using a 2-Steps Direct Polycondensation Process

AbstractA two steps direct polycondensation process of poly(D-lactic acid) (PDLA) synthesis was studied. The melt- polymerization was combined with esterification using p-Toluenesulfonic acid without addition of metal catalyst. The pre-polymer product from the first step was subsequently subjected to solid-state polymerization (SSP) under high temperature and reduced pressure. Prior to the SSP process, the pre-polymer was characterized its thermal property to detect the crystallization temperature (Tc). The pre-polymers were annealed at temperature Tc for 2h until the crystallization peak disappeared. The SSP of pre-polymers was carried out for 30h to produce the satisfied thermal property and high molecular weight. The synthesized poly(D-lactic acid) showed melting temperature of 177oC, weight average molecular weight of 33,300Da, and decomposition temperature of 255oC

Effect of Additive on Crystallization and Mechanical Properties of Polymer Blends of Poly(Lactic Acid) and Poly[(Butylene Succinate)-co-Adipate]

AbstractThe effect of additive on crystallization and mechanical properties of poly(lactic acid) (PLA) and poly(butylene succinate-co-adipate) (PBSA) blend was studied. PLA and PBSA were blended in a twin screw extruder, which incorporated poly(butylene adipate-co-terephthalate) (PBAT) as an additive in PLA/PBSA blend. The ratio of PLA/PBSA was 80/20. The contents of PBAT were varied from 0 to 50 wt%. The thermal properties and crystallization behavior of PLA/PBSA/PBAT blends were analyzed by differential scanning calorimetry. The effect of PBAT contents on non-isothermal crystallization kinetic of the composites was investigated by using Avrami equation. Tensile strength and impact performance of the PLA/PBSA/PBAT blends decreased when increasing PBAT contents. It can be noted that the addition of 20 wt% PBAT showed the maximum impact performance of the PLA/PBSA blends

Effect of Compatibilizer on PLA/PP Blend for Injection Molding

AbstractPolymer blends of poly(lactic acid) and polypropylene were prepared for the application to injection molding products. Due to the phase separation of PLA and PP, the addition of polypropylene-graft-maleic anhydride (PP-g-MAH) as a compatibilizer was studied. The polymer blends were comprised of PLA:PP ratios 80:20 and 20:80 with addition of 1, 3 and 5 wt% of PP-g-MAH. The product samples were processed dry blend with injection molding process and the products were subjected to thermal, mechanical properties and morphology analysis. The thermal analysis confirmed that addition of PP-g-MAH has no effect on crystalline melting temperature of the polymer components as well as no effect on the mechanical properties. The morphology study of the polymer blends confirmed the adhesion of PLA and PP by assistance of PP-g-MAH. The addition of more amount of PP-g-MAH resulted in high polarity of a compatibilizer and decreased the compatibility with PLA. The tensile strength of polymer blends increased with increasing amounts of PLA. The research results confirmed the application of polymer blend system to injection molding process

Prototype Co-Pyrolysis of Used Lubricant Oil and Mixed Plastic Waste to Produce a Diesel-Like Fuel

The co-pyrolysis of used lubricant oil blended with plastic waste, namely high-density polyethylene (HDPE), polypropylene (PP), and polystyrene (PS), to produce a diesel-like fuel was studied. The proportions of the raw materials were optimized using laboratory scale pyrolysis at atmospheric pressure at a final temperature of 450 °C without a catalyst. The ratios of used lubricant oil (Oil) and plastic waste (Oil:HDPE:PP:PS) investigated were 50:30:20:0, 50:30:0:20, 50:0:30:20, and 50:30:10:10 by weight. It was found that the oil produced using an Oil:HDPE:PP:PS ratio of 50:30:20:0 exhibited most of the properties of standard diesel oil as specified by the Ministry of Energy (Thailand), except for its flash point, which was lower than the standard. Therefore, this proportion was utilized for the scaled-up testing in the co-pyrolysis prototype (10 kg/day). Three reactor temperature ranges (less than 400 °C, 400⁻425 °C, and 425⁻450 °C) were studied, and the properties of the oil products were analysed. The oil products produced at 400⁻425 °C exhibited diesel-like fuel properties

Hydrophilic and Hydrophobic Mesoporous Silica Derived from Rice Husk Ash as a Potential Drug Carrier

This work describes the preparation of mesoporous silica by the green reaction of rice husk ash (RHA) with glycerol, followed by the modification and the potential use as a drug carrier. The reaction was carried out at 215 °C for 2 h. The solution was further hydrolyzed with deionized water and aged for various times (24, 48, 120, 360, 528 and 672 h) before calcinations at 500 °C for 24 h. Further treatment of prepared mesoporous silica was performed using trimethylmethoxysilane (TMMS) to obtain hydrophobic Mesoporous silica. For all synthesized silicas, silica contents were as high as 95 wt %, whereas organic residues were less than 3 wt %. RHA-glycerol showed the highest specific surface area with smallest pore diameter (205.70 m2/g, 7.46 nm) when aged for 48 h. The optimal hydrolysis-ageing period of 120 h resulted in 500.7 m2/g specific surface area, 0.655 cm3/g pore volume and 5.23 nm pore diameter. The surface modification of RHA-glycerol occurred through the reaction with TMMS as confirmed by FTIR (Fourier-transform infrared spectroscopy). Ibuprofen was selected as a model drug for the adsorption experiments. The adsorption under supercritical CO2 was carried out at isothermal temperature of 40 °C and 100 bar; % ibuprofen loading of TMMS modified mesoporous silica (TMMS-g-MS) was 6 times less than that of mesoporous silica aged for 24 h (MS-24h) due to the hydrophobic nature of modified mesoporous silica, not surface and pore characteristics. The release kinetics of ibuprofen-loaded mesoporous silicas were also investigated in vitro. The release rate of ibuprofen-loaded MS-24h was much faster than that of ibuprofen-loaded TMMS-g-MS, but comparable to the crystalline ibuprofen. The slower release rate was attributed to the diffusion control and the stability of hydrophobic nature of modified silica. This would allow the design of a controlled release drug delivery system

Preparation of Biodegradable Polymer Copolyesteramides from L-Lactic Acid Oligomers and Polyamide Monomers

AbstractBiodegradable copolyesteramide was synthesized from L-lactic acid oligomers and polyamide monomers to improve the properties of poly(lactic acid). The oligomer was synthesized from L-lactic acid using direct polycondensation process at 170 oC, 30 torr for 7h. p-Toluenesulfonic acid used as a catalyst. From 1H NMR analysis the oligomers have degree of polymerization of ca. 5. The L-lactic acid oligomer (OLLA) was subjected to reacted with ɛ-caprolactam (CLM) with different ratios: 90:10, 80:20, 70:30 and 60:40 using SnCl2·2H2O as a catalyst at 130, 150 and 170 oC pressure 30 torr for 3h. The synthesized polymers were subjected to thermal property analysis using DSC technique and analyzed the functional groups with FT-IR. It was found that the melting temperature of the polymers increased with increasing amounts of CLM but decreased when the amount of CLM exceeded 30 percent. FT-IR analysis confirmed structure of copolyesteramide comprised of amide ide units and lactate unit