scholarly journals Compatibility of Chitosan in Polymer Blends by Chemical Modification of Bio-based Polyesters

Polymers ◽  
2019 ◽  
Vol 11 (12) ◽  
pp. 1939
Author(s):  
Oscar Vernaez ◽  
Katharina Julia Neubert ◽  
Rodion Kopitzky ◽  
Stephan Kabasci
Keyword(s):  
Food Packaging ◽  
Polymer Chains ◽  
Poly Lactic Acid ◽  
Covalent Bonds ◽  
Molecular Weights ◽  
Grafting Reaction ◽  
Internal Mixer ◽  
In Situ Functionalization

For some applications of bioplastics like food packaging or medical devices, applying additives can be necessary to avoid microbial activity and hinder biofilm or fouling formation. A currently promising additive is chitosan (CS), the deacetylated form of the biogenic scaffolding material chitin. Due to its hydrophilicity, chitosan is not compatible with most of the thermoplastic bio-based polymers like poly(lactic acid) (PLA) or polyhydroxyalkanoates (PHA). In this work, compatibilization between chitosan and two selected bio-based polyesters, PLA and poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV), was enhanced by grafting maleic anhydride (MAH) and glycidyl methacrylate (GMA), respectively, onto polymer chains using peroxide. The success of grafting was confirmed via titration methods. The effects of grafting agent and peroxide concentrations on grafting reaction and the physical and thermal properties of the functionalized polyesters were investigated. Compounding of the functionalized polyesters with different weight portions of chitosan was accomplished in a discontinuous internal mixer by in-situ functionalization, followed by blending with chitosan. The titration method, scanning electron microscopy, DSC, FTIR and mechanical characterization of the composites showed good interfacial adhesion and suggest the formation of covalent bonds between functional groups of the polyesters and chitosan, especially for the samples functionalized with GMA. The molecular weights (Mw) of the samples showed a change in the molecular weight related to the thermal degradation of the sample. The Mw of the samples grafted with MAH are lower than those functionalized with GMA. Furthermore, integration of chitosan into non-functionalized PLA polymer matrix showed a nucleating effect, while for PHBV, the increase of crystallinity with the content of chitosan was only observed for grafted PHBV.

scholarly journals Development and Characterization of a Biodegradable PLA Food Packaging Hold Monoterpene–Cyclodextrin Complexes against Alternaria alternata

Polymers ◽  
2019 ◽  
Vol 11 (10) ◽  
pp. 1720 ◽  
Author(s):  
Velázquez-Contreras Friné ◽  
Acevedo-Parra Hector ◽  
Nuño-Donlucas Sergio Manuel ◽  
Núñez-Delicado Estrella ◽  
Gabaldón José Antonio
Keyword(s):  
Alternaria Alternata ◽  
Food Packaging ◽  
Polymer Surface ◽  
Thermal Characterization ◽  
Intermolecular Forces ◽  
Polymer Chains ◽  
Economic Losses ◽  
Poly Lactic Acid ◽  
Injection Process

The fungi of the genus Alternaria are among the main pathogens causing post-harvest diseases and significant economic losses. The consumption of Alternaria contaminated foods may be a major risk to human health, as many Alternaria species produce several toxic mycotoxins and secondary metabolites. To protect consumer health and extend the shelf life of food products, the development of new ways of packaging is of outmost importance. The aim of this work was to investigate the antifungal capacity of a biodegradable poly(lactic acid) (PLA) package filled with thymol or carvacrol complexed in β-cyclodextrins (β-CDs) by the solubility method. Once solid complexes were obtained by spray drying, varying proportions (0.0%, 1.5%, 2.5%, and 5.0 wt%) of β-CD–thymol or β-CD–carvacrol were mixed with PLA for packaging development by injection process. The formation of stable complexes between β-CDs and carvacrol or thymol molecules was assessed by Fourier-transform infrared spectroscopy (FTIR). Mechanical, structural, and thermal characterization of the developed packaging was also carried out. The polymer surface showed a decrease in the number of cuts and folds as the amount of encapsulation increased, thereby reducing the stiffness of the packaging. In addition, thermogravimetric analysis (TGA) revealed a slight decrease in the temperature of degradation of PLA package as the concentration of the complexes increased, with β-CD–carvacrol or β-CDs–thymol complexes acting as plasticisers that lowered the intermolecular forces of the polymer chains, thereby improving the breaking point. Packages containing 2.5% and 5% β-CD–carvacrol, or 5% β-CD–thymol showed Alternaria alternata inhibition after 10 days of incubation revealing their potential uses in agrofood industry.

Response of Modified Poly(lactic acid) to Microwave Radiation

2012 ◽  
Vol 488-489 ◽  
pp. 1393-1397
Author(s):  
Buranin Saengiet ◽  
Wasin Koosomsuan ◽  
Phassakarn Paungprasert ◽  
Rattikarn Khankrua ◽  
Sumonman Naimlang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Lactic Acid ◽  
Microwave Radiation ◽  
Food Packaging ◽  
Impact Resistance ◽  
Poly Lactic Acid ◽  
Polypropylene Glycol ◽  
Heat Accumulation ◽  
The One ◽  
Internal Mixer

The frozen instant food packaging is the one of disposal product, which produced from petroleum–based plastic and has been accumulated worldwide pressuring on the environment. Therefore, the biodegradable plastics have become key candidates in this application. Poly(lactic acid) (PLA) was regarded as one of the most promising biodegradable polymer due to its good mechanical properties. The aim of this work was to study on the freezability and microwavability of PLA through crosslink reaction. For the improvement of the processibility of PLA, hyperbranched polymer (HBP) and polypropylene glycol (PPG) were used as plasticizer. Then the crosslinking of PLA was introduced by addition of peroxide (Luperox101) and triallyl isocyanurate (TAIC) in an internal mixer. Neat and modified PLA samples were characterized and testing for mechanical properties. From the gel content results, it was showed the increased value with the increased content of TAIC due to the denser crosslinked structure of polymer. This result was confirmed by FT-IR spectra. All modified PLA samples showed the higher %strain at break than neat PLA. In addition, impact resistance in frozen state showed the results of modified PLA with 0.1wt% of peroxide and 0.15 wt% of TAIC, was higher than neat PLA. Moreover, this composition also showed the highest microwave response and heat accumulation was suppressed when the specimen was immersed in the water during the test. From the results obtained in this work, the further investigation is needed to pursue and elucidate the relationship between the polymer structure and heat absorption when materials undergo the microwave radiation.

scholarly journals A One-Pot Synthesis and Characterization of Antibacterial Silver Nanoparticle–Cellulose Film

Polymers ◽  
2020 ◽  
Vol 12 (2) ◽  
pp. 440 ◽  
Author(s):  
Qi-Yuan Chen ◽  
Sheng-Ling Xiao ◽  
Sheldon Q. Shi ◽  
Li-Ping Cai
Keyword(s):  
Composite Film ◽  
Food Packaging ◽  
Antibacterial Activities ◽  
Light Transmittance ◽  
Ag Nps ◽  
One Pot ◽  
One Pot Synthesis ◽  
The One

Using N,N-dimethylacetamide (DMAc) as a reducing agent in the presence of PVP-K30, the stable silver nanoparticles (Ag-NPs) solution was prepared by a convenient method for the in situ reduction of silver nitrate. The cellulose–Ag-NPs composite film (CANF) was cast in the same container using lithium chloride (LiCl) giving the Ag-NPs-PVP/DMAc solution cellulose solubility as well as γ-mercaptopropyltrimethoxysilane (MPTS) to couple Ag-NPs and cellulose. The results showed that the Ag-NPs were uniformly dispersed in solution, and the solution had strong antibacterial activities. It was found that the one-pot synthesis allowed the growth of and cross-linking with cellulose processes of Ag-NPs conducted simultaneously. Approximately 61% of Ag-NPs was successfully loaded in CANF, and Ag-NPs were uniformly dispersed in the surface and internal of the composite film. The composite film exhibited good tensile properties (tensile strength could reach up to 86.4 MPa), transparency (light transmittance exceeds 70%), thermal stability, and remarkable antibacterial activities. The sterilization effect of CANF0.04 against Staphylococcus aureus and Escherichia coli exceed 99.9%. Due to low residual LiCl/DMAc and low diffusion of Ag-NPs, the composite film may have potential for applications in food packaging and bacterial barrier.

scholarly journals In-Situ X-Ray Characterization of Fiber Structure during Melt Spinning

2008 ◽  
Vol 3 (3) ◽  
pp. 155892500800300 ◽  
Author(s):  
Michael S. Ellison ◽  
Paulo E. Lopes ◽  
William T. Pennington
Keyword(s):  
Melt Spinning ◽  
Simultaneous Detection ◽  
Polymer Melt ◽  
Polymer Chains ◽  
Degree Of Crystallinity ◽  
Structure Evolution ◽  
X Ray ◽  
Spinning Process

The properties of a polymer are strongly influenced by its morphology. In the case of fibers from semi-crystalline polymers this consists of the degree of crystallinity, the spacing and alignment of the crystalline regions, and molecular orientation of the polymer chains in the amorphous regions. Information on crystallinity and orientation can be obtained from X-ray analysis. In-situ X-ray characterization of a polymer during the melt spinning process is a major source of information about the effects of material characteristics and processing conditions upon structure evolution along the spinline, and the final structure and properties of the end product. We have recently designed and installed an X-ray system capable of in-situ analysis during polymer melt spinning. To the best of our knowledge this system is unique in its capabilities for the simultaneous detection of wide angle and small angle X-ray scattering (WAXS and SAXS, respectively), its use of a conventional laboratory radiation source, its vertical mobility along the spinline, and its ability to simulate a semi-industrial environment. Setup, operation and demonstration of the capabilities of this system is presented herein as applied to the characterization of the melt spinning of isotactic poly(propylene). Crystallinity and crystalline orientation calculated from WAXS patterns, and lamellar long period calculated from SAXS patterns, were obtained during melt spinning of the polymer along the spinline.

A Cross-Scale Characterization of Interface Properties between Carbon Nanotubes and Polymer Matrix

2006 ◽  
Vol 312 ◽  
pp. 217-222 ◽  
Author(s):  
Kausala Mylvaganam ◽  
Liang Chi Zhang
Keyword(s):  
Carbon Nanotubes ◽  
Molecular Dynamics ◽  
Quantum Mechanics ◽  
High Performance ◽  
Mechanical Deformation ◽  
Polymer Chains ◽  
Interface Properties ◽  
Covalent Bonds ◽  
Scale Characterization

This paper discusses the methods of promoting covalent bonds between polymer and carbon nanotubes to make high performance composites. Such methods involve attachment of chemical moieties (i.e. functional groups) to the sidewalls of carbon nanotubes, introduction of mechanical deformation on nanotubes, or generation of radicals on the polymer chains using free radical generators. The implementation of the latter method is demonstrated at both quantum mechanics and molecular dynamics levels.

Synthesis of a Compatibilizer and the Effects of Monomer Concentrations

2014 ◽  
Vol 554 ◽  
pp. 96-100 ◽  
Author(s):  
Nur Syazana Abdullah Sani ◽  
Agus Arsad ◽  
Abdul Razak Rahmat
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Lactic Acid ◽  
Fourier Transforms ◽  
Poly Lactic Acid ◽  
H Nmr ◽  
Grafting Reaction ◽  
Melt Grafting ◽  
Infrared Spectrometer ◽  
Internal Mixer ◽  
Grafting Degree

The aim of this research was to modify Poly (lactic acid) (PLA) and Natural Rubber (NR) using maleic anhydride (MA). The preparation was carried out using internal mixer by free radical melt grafting reaction to produce PLA-g-MA and NR-g-MA as a compatibilizer. The effects of concentrations of MA (3-12 phr) were studied in details. The samples structure of copolymers were then characterized using 1H nuclear magnetic resonance (1H-NMR) and Fourier transforms infrared spectrometer (FTIR). Quantities of grafted MA (% grafting) were characterized by titration analysis and when increasing the monomer used, the quantities of the grafted MA on PLA and NR molecules also increased. The optimum grafting degree for PLA-g-MA and NR-g-MA was at 9 phr of MA with value of 1.63% and 5.02%, respectively.

Synthesis and characterization of novel organosoluble aromatic copolyimides

e-Polymers ◽  
2005 ◽  
Vol 5 (1) ◽  
Author(s):  
Jintian Yang ◽  
Wei Huang ◽  
Yongfeng Zhou ◽  
Deyue Yan ◽  
Xiaohang Wang
Keyword(s):  
Gel Permeation Chromatography ◽  
Polymer Chains ◽  
Polymerization Process ◽  
Synthesis And Characterization ◽  
Aprotic Solvents ◽  
Solution Casting ◽  
Molecular Weights ◽  
Gel Permeation ◽  
Dipolar Aprotic Solvents

AbstractA series of novel aromatic copolyimides was synthesized from pyromellitic dianhydride with the commercial diamine 4,4’-methylenebisaniline (MBA) and the diamine 4,4’-methylenebis(2-tert-butylaniline) (MBTBA) specially designed by ourselves. The solubility of the copolyimides in conventional solvents decreased with the mole ratio of MBTBA to MBA. When MBTBA/MBA was larger than 8/2, the copolyimides are soluble in low boiling point solvents (such as chloroform and tetrahydrofuran) and can form a transparent, flexible, tough film by solution casting. When MBTBA/MBA was between 7/3 and 5/5, the copolyimides are only soluble in dipolar aprotic solvents (such as dimethylformamide and N-methyl-2-pyrrolidone) and form films, too. The copolyimide was precipitated in m-cresol in the polymerization process when MBTBA/MBA was lower than 5/5. The number-average molecular weights of the soluble copolyimides measured by gel permeation chromatography were larger than 5.0·104 and the polydispersity index was higher than 1.5. Only one glass transition of these copolyimides was detected at around 350°C. The copolyimides did not show appreciable decomposition up to 400°C under air and 550°C under nitrogen, and their thermal stability increased a little with the introduction of MBA into the polymer chains.

scholarly journals Preparation and Characterization of Chitosan Nanocomposite Based on Nanoscale Silver and Nanomontmorillonite

2019 ◽  
Vol 2 (2) ◽  
pp. 5-12 ◽  
Author(s):  
Fatemeh- Sadat Ebnerasool ◽  
Negar Motakef Kazemi
Keyword(s):  
Food Packaging ◽  
Solution Method ◽  
In Situ Synthesis ◽  
Diffusion Method ◽  
X Ray ◽  
E Coli ◽  
Packaging Industry ◽  
Scanning Electron

The chitosan nanocomposites were rapidly prepared by simple solution method. This biopolymer matrix was modified by prepared nanoscale silver (Ag) using in situ synthesis from precursor and nanomontmorillonite (NMMT). The samples were characterized by Fourier transform infrared (FTIR) spectroscopy, thermogravimetric analysis (TGA), field emission scanning electron microscopy (FESEM), and energy dispersive x-ray spectroscopy (EDX). The water vapor properties (WVP) of nanocomposites were investigated using gravimetric standard. The antibacterial activity of nanocomposite was measured by the well diffusion method on Muller–Hinton Agar against Escherichia coli (E. coli) by zone inhibition. Based on the obtained results, the nanocomposite can have a good candidate for different applications and food packaging industry.

Sign in / Sign up

Export Citation Format

Share Document