Morphological and thermal properties of photodegradable biocomposite films (original) (raw)
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Biodegradable poly(L-lactic acid)/TiO2 nanocomposites: Thermal properties and degradation
Journal of Applied Polymer Science, 2012
Poly(L-lactic acid)-titanium dioxide nanocomposites (with various loadings of TiO 2 : 0.5, 1, 2, 5, and 10 wt %) were produced by solution casting method. The influence of TiO 2 on thermal properties and crystallinity of PLA was investigated by DSC and FTIR spectroscopy. The TiO 2 nano filler has no significant influence on the characteristic temperatures (T g , T c , and T m ), but has high impact on the crystallinity of these systems. The degree of crystallinity X c significantly increases for PLA nanocomposites loaded with up to 5 wt % of TiO 2 , while for 10 wt % load of TiO 2 it drops below X c of the pure resin. The degrada-tion of the prepared composites was evaluated hydrolytically in 1N NaOH, enzymatically in a-amylase solutions, and under UV irradiation. The catalytic effect of TiO 2 nano particles on the degradation processes under UV light exposure (k ¼ 365 nm) and hydrolytic degradation was confirmed with the increase of the filler content. The opposite effect was identified in enzymatic degradation experiments.
Polymer Testing, 2015
The morphology and thermal stability of melt-mixed poly(lactic acid) (PLA)/poly(ε-caprolactone) (PCL) blend nanocomposites with small amounts of TiO 2 nanoparticles were investigated. The nanoparticles were mostly located in the PLA phase, with good dispersion of individual particles, although significant aggregation was also visible. The thermal stability and degradation behaviour of the different samples were studied using thermogravimetric analysis (TGA) and TGA-Fourier-transform infrared (FTIR) spectroscopy. Neat PCL showed better thermal stability than PLA, but the degradation kinetics revealed that PLA had a higher activation energy of degradation than PCL, indicating its degradation rate more strongly depends on temperature, probably because of a more complex degradation mechanism based on chain scission and re-formation. Blending of PLA and PCL reduced the thermal stabilities of both polymers, but the presence of TiO 2 nanoparticles improved their thermal stability. The nanoparticles also influenced the volatilization of the degradation products from the blend, acted as degradation catalyst and/or retarded the escape of volatile degradation products.
Materials
In order to improve the properties of biodegradable polylactide (PLA), mixtures with polybutylene adipate-co-terephthalate (PBAT) were prepared. PLA is a bio-based and renewable biodegradable material, made from starch. PBAT is a biodegradable polyester for compostable film. In order to improve the composite properties, two types of additives were implemented via melt mixing, a chain extender (CE) and montmorillonite (MMT). CE was used as an interfacial modifier to enhance the adhesion between components. Montmorillonite is a widely studied clay added to polymer nanocomposites. Due to the lamellar structure, it improves the barrier properties of materials. PLA/PBAT films were oriented in the extrusion process and the amounts of filler introduced into the PLA/PBAT nanocomposites were 1.0, 3.0, and 5.0%. The improvement in the PLA barrier properties by the addition of PBAT and 5% of MMT was confirmed as the oxygen permeability decreased almost by a factor of 3. The addition of the bio...
Journal of Applied Polymer Science, 2012
Polylactide (PLA) blends with 0-40 wt % gelatinized starches (GSs) in the presence of plasticizers and compatibilizer for improving interfacial bonding between two phases were prepared. The effects of compatibilizer, type and amount of starch, including type and concentration of plasticizer on the physical, morphological, thermal, and mechanical properties of these films were investigated. Two types of starch (corn and tapioca) were added as fillers, whereas the glycerol amount was varied from 0 to 35 wt % based on starch content. Polyethylene glycol (PEG400) and propylene glycol (PG) were added as plasticizers at four different amounts (5-20 wt %) based on PLA content, while methylenediphenyl diisocyanate was used as a compatibilizer at 1.25 wt % of GS. The results indicated that the presence of glycerol had no effect on the thermal degradation of GS. For PLA plasticization, the plasticized PLA with PEG400 had better properties than that with PG. Water absorption isotherm of the blend films increased as the amount of starches increased; in contrast, the tensile properties decreased progressively with the addition of the GS content. The blend films with gelatinized corn starch had higher tensile properties than those with gelatinized tapioca starch. V
properties of polylactide PLA-based nanocomposite films that were prepared by solvent casting method with polyethylene glycol (PEG), and alumina were studied. PLA/PEG blend showed decrease in tensile strength and Young modulus but increased in elongation in PLA/PEG and increased in crystalline of PLA but decrease in glass transition temperature with the increasing of PEG concentration . A nano blend composites of PLA/PEG/alumina (50/50/4) when compared to PLA/PEG blend indicated that tensile strength , Young modulus and glass transition temperature (Tg) increased with adding alumina nano particles, concentration and barrier properties improvement due to its nucleating and reinforcing function mineral when add nano alumina to PLA/PEG blend . These results indicated that the incorporation of Al2O3 enhanced the Oxygen barrier properties of the PLA.
Synthesis of Nanocomposite Materials for Biodegradable Food Packaging
International Journal of Oil Palm
This paper concerns on synthesis of nancomposite materials, based on poly(D,Llactic acid)/poly(L-lactic acid). The Poly(L,D-lactic acid) (PDLLA) was produced from L,Dlactic acid through direct polycondensation method and poly(L-lactic acid) (PLLA) derived from L-lactide through ring-opening polymerization method. The PDLLA/PLLA films were produced through solvent casting method. The ratio of PDLLA in the PDLLA/PLLA matrix was determined by adjusting PDLLA fraction. The nanoclay used in this experiment were natural clay (Bentonite) and modified organoclay with quaternary ammonium salt (Cloisite 30B). The PLA blend nanocomposites was produced through solution intercalation with sonication. To determine the effect of amounts of nanoclay and sonication period, these two variable were varied. To analyze chemical structure of PLA, the PLA blend film were tested using Fourier Transform Infrared (FTIR). The dispersion of nanoclay on the PLA blend matrix was analyzed using X-Ray Diffraction (XRD) test. The properties of PLA blend nanocomposites film were then characterized using Universal Testing Machine (UTM), Water Vapor Permeability (WVP) test and the enzymatic biodegradability test. The fraction of PDLLA on the PLA blend was fixed 70 % wt. XRD test showed exfoliation of Cloisite 30B in the PLA matrix while the Bentonite was exfoliated as well as intercalated. The addition of nanoclay improved the tensile strength of PLA blend nanocomposites polymer to the number of 56.26 MPa and 37.65 MPa, respectively. Sonication period of PDLLA/PLLA nanocomposite affected the mechanical properties, barrier properties and polymer biodegradability. Moreover, from the WVP test, the barrier properties of the blend polymers was improved and increased twice compared to that of the pure PDLLA/PLLA.
Polymer Degradation and Stability, 2016
Active nanocomposite films based on poly(lactic acid) (PLA), thymol and silver nanoparticles (Ag-NPs) were prepared and characterised. PLA films containing 6 and 8 wt% thymol and 1 wt% Ag-NPs were processed by extrusion to obtain binary and ternary formulations. The addition of thymol and Ag-NPs modified the PLA thermal, optical and barrier properties; in particular water vapour permeability (WVP), maintaining oxygen transmission rate (OTR) values unchanged. Homogeneous surfaces in all films were obtained as proved by FESEM micrographs. The presence of the active additives enhanced the disintegration rate of PLA under composting conditions, which was completed in 14 days. Results suggest that these nanocomposite films could be considered promising degradable active packaging materials with low environmental impact.
Gas Barrier Properties of Biodegradable Polymer Nanocomposites Films
Chemistry and Materials Research, 2014
Bionanocomposites from biopolymers and inorganic nanoparticles are of great interest for packaging materials due to their enhanced physical, thermal, mechanical, and processing characteristics. In this study polylactic acid and titanium oxide (PLA/TiO 2) films were prepared by casting method. The effect of structural, mechanical , thermal, and barrier properties of the nanocomposites were studied. Fourier transform infrared spectroscopy confirmed that no change in bonds of PLA /TiO 2. Increased glass transition temperature and thermal stability, compared with pure PLA. Mechanical properties (Tensile strength, Young Modulus) increased when add 1, 3,and 5wt% TiO 2 compare with PLA(2.3, 2.5, 2.8 and 3)Gpa. Barrier properties (oxygen transmission rate) was decrease when the concentration of TiO 2 is increased in PLA/TiO 2 film as (18, 16, and 14) cm 3. mm/m 2 .day.atm, compare with neat PLA was 20 cm 3. mm/m 2 .day.atm