Biodegradation of Blown Films Based on Poly(lactic acid) under Natural Conditions

Poly(lactic acid) (PLA) films filled with up to 50 wt % softwood flour were prepared by melt compounding and thermocompression. Thermal annealing of the melt was performed at temperatures from 90 C to 120 C, for 45 min. Responses on polymer-filler interactions, viscoelastic properties, crystallinity of PLA as well as PLA-wood flour-filled films were investigated by differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), and scanning electron microscopy (SEM). The effectiveness of fillers on the storage moduli (C) was also calculated. The results reveal that wood flour (WF) in conjunction with thermal annealing affected the melting behavior of PLA matrix, and the glass transition temperature. It was further found that the effectiveness of the wood filler in biocomposites widely improved with thermal annealing as well as with higher WF concentration. Finally, it was found that the compatibility between WF and the PLA matrix can be improved when suitable annealing conditions are applied. V C 2010 Wiley Periodicals, Inc. J Appl

Section: Introductionmentioning

confidence: 99%

Effect of wood flour loading and thermal annealing on viscoelastic properties of poly(lactic acid) composite films

Hrabalova

Gregorová

Wimmer

et al. 2010

“…We have already informed that eq. (3) fails at low M n of PLA 3. Interestingly, the relation between T g and M n is relatively valid for PLACA samples even at low‐molecular weights of the polycondensation products obtained at higher CA concentrations.…”

Section: Resultsmentioning

confidence: 91%

“…In recent years, biodegradable polymers have been investigated extensively for their potential applications in medical and pharmaceutical fields 1–4. Polylactic acid (PLA) is one of the promising biodegradable polymers, which belongs to the group of aliphatic polyesters.…”

Section: Introductionmentioning

confidence: 99%

“…The excellent properties of PLA and its copolymers, such as biodegradability and biocompatibility, predetermine them to be used for medical devices (sutures, bone fixations, and implants) and also drug carriers (nano‐ and microparticles and polymer–drug conjugates) as reported in many publications 5–8. In addition, there are other nonmedical areas of PLA use, which are objects of both scientific and practical use interest due the possibility of PLA production based on environmental friendly technologies availing renewable materials (biodegradable packaging, materials based on renewable resources) 3, 9, 10…”

Section: Introductionmentioning

confidence: 99%

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Functionalization of polylactic acid through direct melt polycondensation in the presence of tricarboxylic acid

Kucharczyk

Poljanšek

Sedlařík

et al. 2011

Self Cite

The goal of the article was to describe the preparation of carboxyl-functionalized polylactic acid (PLA) through the method of direct melt copolycondensation of lactic and citric acid (CA). In addition, detailed study of copolycondensation process, its limitations and investigation of the reaction products properties are another issue this article deals with. The effect of tricarboxylic CA on the resulting properties of the functionalized lactic acid (LA) polycondesates was studied in a wide range of LA/CA molar ratios. The influence of CA on molecular weight, thermal and physicochemical properties, and chemical structure of the products was investigated, using viscometric measurements of the polymer solutions, gel permeation chromatography, 1 H nuclear magnetic resonance spectroscopy, differential scanning calorimetry, acidity number determination, and Fourier-transform infrared and ultraviolet spectroscopy. The results show the significant effect of CA on the structure and physicochemical properties as well as high efficiency of functionalization. Furthermore, a branched structure was detected at low CA concentrations, while higher CA content leads to termination of the polycondensates chains by citryl units and a reduction in the molecular weight. Here, insights on the characterization methods of PLA-based materials are given by various experimental techniques.

“…6 Because of the fact that the whey is often considered undesirable waste, there is a significant interest in finding a new method for its utilization. 6,7 The polymerization step required LA of high monomer purity, which is technologically and financially demanding. However, as was previously mentioned, biotechnologically prepared LA can contain impurities such as organic acids, residual proteins, and inorganic compounds, which could affect the polymerization step.…”

Section: Introductionmentioning

confidence: 99%

Influence of natural inorganic impurity on the synthesis of poly(L‐lactic acid), properties and nanofabrication

Kucharczyk¹,

Miroslava²,

Stloukal³

et al. 2013

This work is focused on determination of the effect of a calcium-based inorganic impurity originating from biotechnological L-lactic acid production from cheese whey on the synthesis of poly(L-lactic acid). The influence of the impurity was investigated in the range of 0 to 1 wt % and the product properties were studied by analytical techniques GPC, FTIR-ATR, acid end group analysis and DSC. The final product was used to prepare submicron particles, which were analyzed by dynamic light scattering and electron microscopy. Results show a moderate reduction in molecular weight in connection with an increase in the amount of the impurity up to 0.75 wt %. Further increase in the concentration of the impurity caused decomposition. Investigating the thermal properties reveals a noticeable reduction in the melting temperature and a slight decrease in glass transition temperature. The prepared submicron particles had a Z-average diameter of between 280 and 520 nm, depending on the emulsifying system, and the presence of the inorganic impurity seems to play no role during particle formation.