scholarly journals Efecto de la adición de copolímeros reactivos a mezclas de PLA/ATP

2020 ◽  
pp. 20-26
Author(s):  
Maria Cristina KANTUN-UICAB ◽  
Isis RODRÍGUEZ-SÁNCHEZ ◽  
Francisco Javier RODRÍGUEZ-GONZÁLEZ ◽  
Juan Gregorio HORTELANO-CAPETILLO
Keyword(s):  
Epoxy Group ◽  
Thermoplastic Starch ◽  
Hydroxyl Groups ◽  
Melt Mixing ◽  
Acrylic Copolymer ◽  
Reactive Compatibilization ◽  
Torque Rheometry ◽  
Viscosity Increase ◽  
End Groups ◽  
Acrylic Copolymers

In this work, the reactive compatibilization of Polylactic Acid/Thermoplastic Starch (PLA/TPS, 80/20% w/w) blends using acrylic copolymers of methyl methacrylate-glycidyl methacrylate (MMA-GMA) was examined. The compatibilization was studied using torque rheometry, thermal analysis (DSC), Scanning Electron Microscopy (SEM) and mechanical properties. During melt mixing, the torque of PLA/TPS blends decreased, this was related to the breakup of starch chains. The addition of MMA-GMA copolymer increased the torque during the mixing period. This torque increasing is evidence of a viscosity increase and it was related to the reactions between the epoxy group present in the acrylic copolymer, the end-groups of the PLA and TPS hydroxyl groups. The morphologies of the compatibilized blends showed a decrease in the particle size of the TPS domains and an increase in elongation of 30%. The reactive compatibilization is an interesting technique to expand the property range of PLA materials, which can potentially substitute oil-based materials.

scholarly journals Study of the Preparation and Properties of TPS/PBSA/PLA Biodegradable Composites

2021 ◽  
Vol 5 (2) ◽  
pp. 48
Author(s):  
Yuxuan Wang ◽  
Yuke Zhong ◽  
Qifeng Shi ◽  
Sen Guo
Keyword(s):  
Mechanical Properties ◽  
Heat Resistance ◽  
Thermoplastic Starch ◽  
Sem Analysis ◽  
Infrared Spectrometry ◽  
Fourier Transform Infrared Spectrometry ◽  
Melt Mixing ◽  
Two Phase ◽  
Biodegradable Composites ◽  
Phase Compatibility

Thermoplastic starch/butyl glycol ester copolymer/polylactic acid (TPS/PBSA/PLA) biodegradable composites were prepared by melt-mixing. The structure, microstructure, mechanical properties and heat resistance of the TPS/PBSA/PLA composites were studied by Fourier-transform infrared spectrometry (FTIR), scanning electron microscopy (SEM), tensile test and thermogravimetry tests, respectively. The results showed that PBSA or PLA could bind to TPS by hydrogen bonding. SEM analysis showed that the composite represents an excellent dispersion and satisfied two-phase compatibility when the PLA, TPS and PBSA blended by a mass ration of 10, 30, and 60. The mechanical properties and the heat resistance of TPS/PBSA/PLA composite were improved by adding PLA with content less than 10%, according to the testing results.

scholarly journals Reinforcement of Thermoplastic Corn Starch with Crosslinked Starch/Chitosan Microparticles

Polymers ◽  
2018 ◽  
Vol 10 (9) ◽  
pp. 985 ◽  
Author(s):  
Diana Paiva ◽  
André Pereira ◽  
Ana Pires ◽  
Jorge Martins ◽  
Luísa Carvalho ◽  
...  
Keyword(s):  
Water Solubility ◽  
Corn Starch ◽  
Polymer Network ◽  
Xrd Analysis ◽  
Thermoplastic Starch ◽  
Interpenetrating Polymer Network ◽  
Melt Mixing ◽  
Chitosan Microparticles ◽  
Polysaccharide Composition ◽  
Low Solubility

Microparticles of corn starch and chitosan crosslinked with glutaraldehyde, produced by the solvent exchange technique, are studied as reinforcement fillers for thermoplastic corn starch plasticized with glycerol. The presence of 10% w/w chitosan in the microparticles is shown to be essential to guaranteeing effective crosslinking, as demonstrated by water solubility assays. Crosslinked chitosan forms an interpenetrating polymer network with starch chains, producing microparticles with a very low solubility. The thermal stability of the microparticles is in agreement with their polysaccharide composition. An XRD analysis showed that they have crystalline fraction of 32% with Va-type structure, and have no tendency to undergo retrogradation. The tensile strength, Young’s modulus, and toughness of thermoplastic starch increased by the incorporation of the crosslinked starch/chitosan microparticles by melt-mixing. Toughness increased 360% in relation to unfilled thermoplastic starch.

Acute clouding of hydrophilic acrylic copolymer intraocular lenses:four cases report

2019 ◽  
Author(s):  
Xiaochen Wang ◽  
Yusen Huang ◽  
Xiaoming Wu
Keyword(s):  
Temperature Fluctuation ◽  
The Other ◽  
Intraocular Lenses ◽  
Transient Temperature ◽  
Acrylic Copolymer ◽  
Case Presentation ◽  
Temperature Changes ◽  
Acrylic Copolymers ◽  
Handling Methods ◽  
Phacoemulsification Cataract Surgery

Abstract Background: Intraoperative acrylic intraocular lenses (IOLs) transient clouding of several kinds of hydrophilic IOLs have been reported due to temperature changes. However, we ignored the particularity of its material and the handling methods. Case presentation: We present four cases of acute clouding of hydrophilic acrylic intraocular lenses (IOLs). Four patients underwent phacoemulsification cataract surgery with implantation of L-312, 809M, and 839M IOLs, respectively. The IOLs became opaque in varying degrees during surgery. Lens replacement was performed immediately in one case, while the cloudy IOLs were remained in the other three cases. Postoperatively, all IOLs recovered transparency. Conclusions：Temperature fluctuation was the cause of the acute opacification of these IOLs made of hydrophilic acrylic copolymers, which reminds us of attaching importance to the temperature of IOL storage and delivery in winter months. Keywords: Opacification, transient, temperature, material, cataract.

scholarly journals The Formation of Glycerol Oligomers with Two New Types of End Groups in the Presence of a Homogeneous Alkaline Catalyst

Polymers ◽  
2019 ◽  
Vol 11 (1) ◽  
pp. 144 ◽  
Author(s):  
Dawid Kansy ◽  
Kornelia Bosowska ◽  
Krystyna Czaja ◽  
Anna Poliwoda
Keyword(s):  
Catalyst Concentration ◽  
Reaction Medium ◽  
Hydroxyl Groups ◽  
Ionization Mass ◽  
Carboxylate Group ◽  
Reaction Products ◽  
Direct Infusion ◽  
Alkaline Catalyst ◽  
End Groups ◽  
First Time

The purpose of this work was to synthesize and characterize oligoglycerols with the chains of more than four repeating units. Those oligoglycerols may have some interesting applications, among others, as polyoxyalkylation starters. The glycerol oligomerization process was carried out during 12 h, at 230 °C, under the pressure of 0.4 bar, with the use of sodium carbonate as a homogeneous basic catalyst; various concentrations of the catalyst in the reaction medium were used. The reaction products were analyzed with the use of direct infusion electrospray ionization mass spectrometry (ESI-MS), nuclear magnetic resonance (13C NMR) and Fourier transform infrared spectroscopy (FTIR) techniques. Based on the analytical findings, the compositions of the obtained product mixtures and the structures of oligoglycerols present in individual fractions were determined. The effect of catalyst concentration on the composition of the post-reaction mixture was observed. Moreover, in addition to the conventional linear oligomers (α,α-oligoglycerols), two new types of the oligomers were for the first time detected in the post-reaction mixture: one with two hydroxyl groups and the other with a carboxylate group at the α-carbon atom.

scholarly journals Pine Resin Derivatives as Sustainable Additives to Improve the Mechanical and Thermal Properties of Injected Moulded Thermoplastic Starch

2020 ◽  
Vol 10 (7) ◽  
pp. 2561 ◽  
Author(s):  
Miguel Aldas ◽  
Cristina Pavon ◽  
Juan López-Martínez ◽  
Marina Patricia Arrieta
Keyword(s):  
Corn Starch ◽  
Mechanical Performance ◽  
Thermoplastic Starch ◽  
Dehydroabietic Acid ◽  
Hydroxyl Groups ◽  
Mechanical And Thermal Properties ◽  
Pine Resin ◽  
Pentaerythritol Ester ◽  
Hydrogen Bond Interactions ◽  
Gum Rosin

Fully bio-based materials based on thermoplastic starch (TPS) were developed starting from corn starch plasticized with glycerol. The obtained TPS was further blended with five pine resin derivatives: gum rosin (GR), disproportionated gum rosin (dehydroabietic acid, RD), maleic anhydride modified gum rosin (CM), pentaerythritol ester of gum rosin (LF), and glycerol ester of gum rosin (UG). The TPS–resin blend formulations were processed by melt extrusion and further by injection moulding to simulate the industrial conditions. The obtained materials were characterized in terms of mechanical, thermal and structural properties. The results showed that all gum rosin-based additives were able to improve the thermal stability of TPS, increasing the degradation onset temperature. The carbonyl groups of gum rosin derivatives were able to interact with the hydroxyl groups of starch and glycerol by means of hydrogen bond interactions producing a significant increase of the glass transition temperature with a consequent stiffening effect, which in turn improve the overall mechanical performance of the TPS-resin injected moulded blends. The developed TPS–resin blends are of interest for rigid packaging applications.

scholarly journals Relaxation Dynamics in Polyethylene Glycol/Modified Hydrotalcite Nanocomposites

Polymers ◽  
2018 ◽  
Vol 10 (11) ◽  
pp. 1182 ◽  
Author(s):  
Rossella Arrigo ◽  
Diego Antonioli ◽  
Massimo Lazzari ◽  
Valentina Gianotti ◽  
Michele Laus ◽  
...  
Keyword(s):  
Polyethylene Glycol ◽  
Polymer Matrix ◽  
Complex Viscosity ◽  
Gas Chromatography Mass Spectrometry ◽  
Hydroxyl Groups ◽  
Thermal Treatments ◽  
Relaxation Dynamics ◽  
Unusual Behavior ◽  
Melt Mixing ◽  
Grafting Reactions

Polyethylene glycol-based nanocomposites containing an organo-modified hydrotalcite with loadings ranging from 0.5 to 5 wt.% were prepared by melt mixing performed just above the melting point of the polymer matrix. In these conditions, the dispersion of the nanofiller within the polymer matrix was quite homogeneous as revealed by TEM analyses. The effect of various thermal treatments and filler loadings was thoroughly investigated by means of rheological, morphological and gas chromatography-mass spectrometry, hyphenated to thermogravimetry analysis tests. Unfilled polyethylene glycol exhibited a continuous decrease in complex viscosity upon heating. In contrast, the complex viscosity of nanocomposites containing nanofiller loadings higher than 1 wt.% showed first a decrease, followed by an increase in the complex viscosity as the temperature increases, exhibiting a minimum between 130 and 140 °C. Annealing at 180 °C for different times further increased the viscosity of the system. This unusual behavior was explained by the occurrence of grafting reactions between the –OH terminal groups of the polyethylene glycol chains and the hydroxyl groups of the organo-modified filler, thus remarkably affecting the relaxation dynamics of the system.

Synthesis and Characterization of Carboxyl-Terminated Hyperbranched Polyester

2014 ◽  
Vol 665 ◽  
pp. 327-330
Author(s):  
Shi Jie Niu ◽  
Jian Wang ◽  
Yu Qing Bai ◽  
Ming Tao Run
Keyword(s):  
Glass Transition ◽  
Sodium Acetate ◽  
Succinic Anhydride ◽  
Molar Ratio ◽  
Synthesis And Characterization ◽  
Hydroxyl Groups ◽  
Hyperbranched Polyester ◽  
End Groups ◽  
Lower Glass Transition Temperature

In order to prepare carboxyl-terminated hyperbranched polyester (HBP-COOH), succinic anhydride was used to modify hydroxyl-terminated hyperbranched polyester (HBP-OH), and the influences of the solvents, catalysts and time on the product’s structure were investigated. When THF is used as the solvent, sodium acetate as the catalyst, the molar ratio of succinic anhydride and hydroxyl groups is 3:1, and the reaction time is 6 h at 65°C, the modification extent of the hydroxyl groups is about 99% with about 95% yield. HBP-COOH has much lower glass transition temperature than that of HBP-OH due to its long and flexible end-groups.

Dispersion of Wood Microfibers in a Matrix of Thermoplastic Starch and Starch–Polylactic Acid Blend

2007 ◽  
Vol 1 (1) ◽  
pp. 71-77 ◽  
Author(s):  
Ayan Chakraborty ◽  
Mohini Sain ◽  
Mark Kortschot ◽  
Sean Cutler
Keyword(s):  
Polylactic Acid ◽  
Polymer System ◽  
Cellulose Fibers ◽  
Thermoplastic Starch ◽  
Processing Parameters ◽  
Percentage Increase ◽  
Melt Mixing ◽  
Cellulose Microfibers ◽  
Solution Cast ◽  
Microscopy Images

The successful dispersion of cellulose fibers of submicrometer diameter in polymers has been restricted to solution-cast films so far. In this work, the dispersion of microfibers in biopolymers was investigated by melt-mixing using conventional processing equipment. Thermoplastic starch and a blend of starch and polylactic acid (PLA) were used as matrix materials. A suspension of cellulose microfibers less than 1 μm in diameter was prepared in water. This microfiber suspension was poured into molten thermoplastic starch to obtain fiber loadings up to 2%. The composites were compression molded into thin films roughly 0.25 mm thick. there was a 10% increase in tensile strength and a 50% increase in stiffness with each percentage increase in microfiber loading in the starch polymer. Similar improvement in tensile properties was also noted for a polymer system prepared by blending starch and PLA. Laser confocal microscopy images were analyzed to quantify microfiber dispersion at different composite processing parameters. This was the first work where successful dispersion of cellulose fibers of submicrometer was achieved in a composite prepared solely by the melt-mixing process.

End groups in acrylic copolymers. 1. Identification of end groups by carbon-13 NMR

1988 ◽  
Vol 21 (6) ◽  
pp. 1598-1603 ◽  
Author(s):  
K. R. Carduner ◽  
R. O. Carter ◽  
M. Zinbo ◽  
J. L. Gerlock ◽  
D. R. Bauer
Keyword(s):  
End Groups ◽  
Acrylic Copolymers

Nanocomposites Based on Acrylic Copolymer, Iron Lignosulfonate and ZnO Nanoparticles Used as Wood Preservatives

2009 ◽  
Vol 151 ◽  
pp. 139-144 ◽  
Author(s):  
Lucia Dumitrescu ◽  
Dana Perniu ◽  
Ileana Manciulea
Keyword(s):  
Zno Nanoparticles ◽  
Sol Gel ◽  
Ethyl Acrylate ◽  
Wood Preservation ◽  
Acrylic Copolymer ◽  
Water Emulsion ◽  
Afm Analysis ◽  
Acrylic Copolymers ◽  
Inorganic Nanomaterials

The paper presents research concerning the synthesis and characterization of some new nanocomposite used as wood coating nanomaterials, consisting of a hybrid of organic (functionalized acrylic copolymers with iron lignosulfonate) and inorganic nanomaterials (ZnO nanoparticles obtained by sol-gel process). The presence of acrylic copolymers in water emulsion (based on monomers ethyl acrylate, butyl acrylate, acrylonitrile and the lignin derivative iron lignosulfonate) and ZnO nanoparticles enables the formation of a crosslinked nanometric network of inorganic and organic domains, emphasized by AFM analysis. The interphase characterization of the nanostructured materials synthesized was performed using FT-IR analysis. Considering the biocide activity for the acrylic copolymers, the lignin derivative iron lignosulfonate and ZnO nanoparticles, the obtained nanocomposites were biologically investigated and proposed as wood preservation agents.

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