scholarly journals Preparations of Poly(lactic acid) Dispersions in Water for Coating Applications

Polymers ◽  
2021 ◽  
Vol 13 (16) ◽  
pp. 2767
Author(s):  
Giada Belletti ◽  
Sara Buoso ◽  
Lucia Ricci ◽  
Alejandro Guillem-Ortiz ◽  
Alejandro Aragón-Gutiérrez ◽  
...  
Keyword(s):  
Lactic Acid ◽  
Gel Permeation Chromatography ◽  
Sem Analysis ◽  
Water Phase ◽  
Poly Lactic Acid ◽  
Water Emulsion ◽  
Preparation Conditions ◽  
Ft Ir ◽  
Homogenization Methods ◽  
Oil In Water Emulsion

A green, effective methodology for the preparation of water-based dispersions of poly(lactic acid) (PLA) for coating purposes is herein presented. The procedure consists of two steps: in the first one, an oil-in-water emulsion is obtained by mixing a solution of PLA in ethyl acetate with a water phase containing surfactant and stabilizer. Different homogenization methods as well as oil/water phase ratio, surfactant and stabilizer combinations were screened. In the second step, the quantitative evaporation of the organic provides water dispersions of PLA that are stable, at least, over several weeks at room temperature or at 4 °C. Particle size was in the 200–500 nm range, depending on the preparation conditions, as confirmed by scanning electron microscope (SEM) analysis. PLA was found not to suffer significant molecular weight degradation by gel permeation chromatography (GPC) analysis. Furthermore, two selected formulations with glass transition temperature (Tg) of 51 °C and 34 °C were tested for the preparation of PLA films by drying in PTFE capsules. In both cases, continuous films that are homogeneous by Fourier-transform infrared spectroscopy (FT-IR) and SEM observation were obtained only when drying was performed above 60 °C. The formulation with lower Tg results in films which are more flexible and transparent.

Synthesis and RGD peptide modification of poly{(lactic acid)-co-[(glycolic acid )-alt-(L-lysine)]}

e-Polymers ◽  
2008 ◽  
Vol 8 (1) ◽  
Author(s):  
Qiongjiao Yan ◽  
Juan Li ◽  
Shipu Li ◽  
Yixia Yin ◽  
Ping Zhang
Keyword(s):  
Lactic Acid ◽  
Glycolic Acid ◽  
Gel Permeation Chromatography ◽  
Rgd Peptide ◽  
Poly Lactic Acid ◽  
H Nmr ◽  
Peptide Modification ◽  
A Cell ◽  
Ft Ir ◽  
Cell Affinity

AbstractA new polymer poly{(lactic acid)-co-[(glycolic acid)-alt-(L-lysine)]} (poly[LA-co-(Glc-alt-Lys)]) was synthesized and modified with a cell adhesion peptide, Gly-Arg-Gly-Asp-Tyr (GRGDY, abbreviated as RGD). The process for preparing poly[LA-co-(Glc-alt-Lys)]/RGD involved four steps: Firstly, (3S)-3-[4- (benzyloxycarbonylamino)butyl]morpholine-2,5-dione (BMD) was synthesized by bromoacetyl bromide and Nε-(benzyloxycarbonyl)-L-lysine [L-Lys(Z)]. Secondly, poly{(lactic acid)-co-[(glycolic acid)-alt-(Nεn-benzyloxycarbonyl-L-lysine)]} (poly{LAco-[ Glc-alt-Lys(z)]}) was obtained by copolymerization of D,L-lactide and BMD. Then, poly[LA-co-(Glc-alt-Lys)] was synthesized by catalytic hydrogenation of poly{LA-co-[Glc-alt-Lys(z)]}. Finally, poly[LA-co-(Glc-alt-Lys)] was modified with RGD peptide in the presence of 1,1́-carbonyldiimidazole (CDI). The structures of poly[LA-co-(Glc-alt-Lys)]/RGD and its precursors were characterized by FT-IR, 1H NMR, 13C NMR, MS, gel permeation chromatography (GPC), amino acid analysis(AAA). RSC96 cells were used to evaluate the cell affinity of the poly[LAco-( Glc-alt-Lys)]/RGD films and poly(D,L-lactide) (PDLLA ) films. The results of cell culture showed that poly[LA-co-(Glc-alt-Lys)]/RGD was more beneficial to cell adherence and growth than PDLLA.

Preparation of Porous Poly(Lactic Acid)/Hydroxyapatite Microspheres Intended for Injectable Bone Substitutes

2005 ◽  
Vol 284-286 ◽  
pp. 819-822 ◽  
Author(s):  
Fukue Nagata ◽  
Tatsuya Miyajima ◽  
Kay Teraoka ◽  
Yoshiyuki Yokogawa
Keyword(s):  
Lactic Acid ◽  
Bone Ingrowth ◽  
Bone Substitutes ◽  
Single Step ◽  
Poly Lactic Acid ◽  
Biodegradable Microspheres ◽  
Water Emulsion ◽  
Internal Water ◽  
Oil In Water ◽  
Oil In Water Emulsion

Porous biodegradable microspheres were successfully obtained by an improvement single step and surfactant-free emulsion solvent evaporation method. The organic phase composed of PLA and dichloromethane was stirred in aqueous phase including Ca2+ ions to yield oil in water emulsion. During emulsification, stirring rate was increased so as to produce the W/O/W emulsion that results in microspheres with internal pores. The interface of internal water/oil was stable in W/O/W emulsion, which was explained that the bond between Ca2+ ions and carboxyl group of poly(lactic acid) would be stabilized the internal water/oil interface. Adding PO4 3- aqueous solution prompted to precipitate low crystallized hydroxyapatite on the external oil/water interface, and the precipitated hydroxyapatite would stabilizied microspheres formation. The resulting microspheres were approximately 100-500 µm with internal spherical pores of 10-200 µm in diameter. The porous biodegradable microspheres were expected to be utilized as injectable bone substitutes that allow bone ingrowth and bone regeneration.

Formation of Hydroxycarbonate Apatite Layer on Poly(Lactic Acid) Composites in Simulated Body Fluid

2005 ◽  
Vol 284-286 ◽  
pp. 489-492 ◽  
Author(s):  
Hirotaka Maeda ◽  
Toshihiro Kasuga ◽  
Masayuki Nogami
Keyword(s):  
Lactic Acid ◽  
Simulated Body Fluid ◽  
Zeta Potential ◽  
Calcium Chloride ◽  
Composite Membrane ◽  
Body Fluid ◽  
Poly Lactic Acid ◽  
Zeta Potentials ◽  
Carbonate Ion ◽  
Ft Ir

Hydroxycarbonate apatite (HCA), which formed on a poly(lactic acid) (PLA) composite membrane containing vaterite or calcium chloride after soaking in simulated body fluid, was examined to clarify the importance of the ceramic phases in the composites. FT-IR spectra showed that the ratio of CO3/PO4 in the infrared adsorption bands of HCA formed on the PLA composite containing vaterite was much larger than that of HCA formed on the PLA composite containing calcium chloride. Substitution of carbonate ion in hydroxyapatite is believed to be strongly influenced by ceramic phases in the composites. The zeta potentials of HCA formed on the PLA composite containing vaterite or calcium chloride was -6 mV or -17 mV, respectively. The zeta potential may be influenced by the amount of carbonate ion in hydroxyapatite.

scholarly journals Impact Toughness and Ductility Enhancement of Biodegradable Poly(lactic acid)/Poly(ε-caprolactone) Blends via Addition of Glycidyl Methacrylate

2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
Wei Kit Chee ◽  
Nor Azowa Ibrahim ◽  
Norhazlin Zainuddin ◽  
Mohd Faizal Abd Rahman ◽  
Buong Woei Chieng
Keyword(s):  
Lactic Acid ◽  
Impact Strength ◽  
Glycidyl Methacrylate ◽  
Interfacial Adhesion ◽  
Tensile Modulus ◽  
Sem Analysis ◽  
Poly Lactic Acid ◽  
Biodegradable Poly ◽  
Interfacial Compatibility ◽  
The Impact

Poly(lactic acid) (PLA)/poly(ε-caprolactone) (PCL) blends were prepared via melt blending technique. Glycidyl methacrylate (GMA) was added as reactive compatibilizer to improve the interfacial adhesion between immiscible phases of PLA and PCL matrices. Tensile test revealed that optimum in elongation at break of approximately 327% achieved when GMA loading was up to 3wt%. Slight drop in tensile strength and tensile modulus at optimum ratio suggested that the blends were tuned to be deformable. Flexural studies showed slight drop in flexural strength and modulus when GMA wt% increases as a result of improved flexibility by finer dispersion of PCL in PLA matrix. Besides, incorporation of GMA in the blends remarkably improved the impact strength. Highest impact strength was achieved (160% compared to pure PLA/PCL blend) when GMA loading was up to 3 wt%. SEM analysis revealed improved interfacial adhesion between PLA/PCL blends in the presence of GMA. Finer dispersion and smooth surface of the specimens were noted as GMA loading increases, indicating that addition of GMA eventually improved the interfacial compatibility of the nonmiscible blend.

scholarly journals Investigation on compatibility of PLA/PBAT blends modified by epoxy-terminated branched polymers through chemical micro-crosslinking

e-Polymers ◽  
2020 ◽  
Vol 20 (1) ◽  
pp. 39-54 ◽  
Author(s):  
Bo Wang ◽  
Yujuan Jin ◽  
Kai’er Kang ◽  
Nan Yang ◽  
Yunxuan Weng ◽  
...  
Keyword(s):  
Lactic Acid ◽  
Glass Transition ◽  
Sem Analysis ◽  
Branched Polymers ◽  
Poly Lactic Acid ◽  
Elongation At Break ◽  
Butylene Terephthalate ◽  
The Difference ◽  
Physical And Chemical ◽  
The Impact

AbstractIn this study, a type of epoxy-terminated branched polymer (ETBP) was used as an interface compati- bilizer to modify the poly lactic acid (PLA)/poly(butylene adipate-co-butylene terephthalate) (PBAT) (70/30) blends. Upon addition of ETBP, the difference in glass transition temperature between PLA and PBAT became smaller. By adding 3.0 phr of ETBP, the elongation at break of the PLA/PBAT blends was found increased from 45.8% to 272.0%; the impact strength increased from 26.2 kJ·m−2 to 45.3 kJ·m−2. In SEM analysis, it was observed that the size of the dispersed PBAT particle decreased with the increasing of ETBP content. These results indicated that the compatibility between PLA and PBAT can be effectively enhanced by using ETBP as the modifier. The modification mechanism was discussed in detail. It proposes that both physical and chemical micro-crosslinking were formed, the latter of which was confirmed by gel content analysis.

Characterization of Electrospun Poly(Lactic Acid)/polyaniline Blend Nanofibers

2011 ◽  
Vol 332-334 ◽  
pp. 317-320 ◽  
Author(s):  
Hui Qin Zhang
Keyword(s):  
Lactic Acid ◽  
Composite Nanofibers ◽  
Weight Ratio ◽  
Electrospinning Process ◽  
Poly Lactic Acid ◽  
X Ray Diffraction ◽  
Sem Images ◽  
X Ray ◽  
Ft Ir

In this study, composite nanofibers of polyaniline doped with dodecylbenzene sulfonic acid (PANI-DBSA) and Poly(lactic acid) (PLA) were prepared via an electrospinning process. The surface morphology, thermal properties and crystal structure of PLA/PANI-DBSA nanofibers are characterized using Fourier transform infrared spectroscopy (FT-IR), wide-angle x-ray diffraction (WAXD) and scanning electron microscopy (SEM). SEM images showed that the morphology and diameter of the nanofibers were affected by the weight ratio of blend solution.

Transmission FT-IR Study on the Adsorption and Reactions of Lactic Acid and Poly(lactic acid) on TiO2

2010 ◽  
Vol 114 (41) ◽  
pp. 17720-17727 ◽  
Author(s):  
Yi-Kwan Chen ◽  
Yu-Feng Lin ◽  
Zih-Wei Peng ◽  
Jong-Liang Lin
Keyword(s):  
Lactic Acid ◽  
Poly Lactic Acid ◽  
Ft Ir ◽  
Ir Study

scholarly journals Feasibility of Reprocessing Natural Fiber Filled Poly(lactic acid) Composites: An In-Depth Investigation

2017 ◽  
Vol 2017 ◽  
pp. 1-10 ◽  
Author(s):  
Sujal Bhattacharjee ◽  
Dilpreet S. Bajwa
Keyword(s):  
Lactic Acid ◽  
Natural Fiber ◽  
Environmental Concern ◽  
Wood Flour ◽  
Gel Permeation Chromatography ◽  
Thermomechanical Properties ◽  
Poly Lactic Acid ◽  
Filler Concentration ◽  
Scanning Calorimetry ◽  
Abrupt Decrease

Poly(lactic acid) (PLA) based composites are biodegradable; their disposal after single use may be needless and uneconomical. Prodigal disposal of these composites could also create an environmental concern and additional demand for biobased feedstock. Under these circumstances, recycling could be an effective solution, since it will widen the composite service life and prevent the excessive use of natural resources. This research investigates an in-depth impact of recycling on the mechanical and thermomechanical properties of oak wood flour based PLA composites. Two composite formulations (30 and 50 wt% filler), each with 3 wt% coupling agent (PLA-g-MA), were produced and reprocessed six times by extrusion followed by injection molding. Measurements of fiber length and molecular weight of polymer were, respectively, carried out by gel permeation chromatography (GPC). Scanning electron microscopy (SEM), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and Fourier transform infrared spectroscopy (FTIR) tools were used to study morphological and molecular alterations. With consecutive recycling, PLA composites showed a gradual decrease in strength and stiffness properties and an increase in strain properties. The 50% and 30% filler concentration of fibers in the composite showed an abrupt decrease in strength properties after six and two reprocessing cycles, respectively.

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