• Clean Technology
• /
• v.23 no.2
• /
• pp.133-139
• /
• 2017

Bio-based plastics containing the biomass content higher than 25 wt% have been considered as environment-friendly materials due to their effects on the reduction in the $CO_2$ emission and petroleum consumption as well as biodegradability after use. In this study, poly vinyl chloride, plant-derived plasticizers, by adding a biodegradable catalyst was observed a change in the biodegradability and physical properties. To produce the oxidative decomposition transparent bio film, which is broken down in the initial percent elongation and physical properties such as tensile strength, it was to test the safety of the product as a food packaging material. Poly vinyl chloride, primary plasticizer, secondary plasticizer, anti fogging agent, the combined stabilizer were mixed in a high speed mixer, then extruded using an extrusion molding machine, after cooling, winding, to produce a oxidative decomposition transparent bio film and the control film, with a thickness of $12{\mu}m$ through winder role. Mechanical properties tensile strength, elongation, and the maximum load elongation and biodegradation test. Transparent bio film produced by biodegradation catalyst is compared with the control film. Tensile strength and elongation of films were found to be no significant difference. Further, as a result of the biodegradation test for 45 days based on the ASTM D6954-04 method, biodegrability of film is 61.4%.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.68 no.3
• /
• pp.207-215
• /
• 2023

This study was compared the soil environment and growth and yield of onion (Allium cepa L.) treated with non-mulching (NM) and mulching polyethylene film (PEF) and two biodegradable films (BFI and BFII) commonly used in farmhouses. Visual observation confirmed the degradation of BFI and BFII films after 150 days after tansplanting (DAT). BFII increased light penetration into the films and reduced the weight maintenace after 180 DAT, with a high decompostion at 30 days after soil tilling. Soil moisture contents much fluctuated between -14 kP and - 0 kPa in NM plots, increasing the minimum soil temperature of BFI plots. Mulching treatments decreased soil organic matter contents but did not subtantially increase soil mineral nutrients, soil bulk density, and number of bacteria compared to those of NM plots. Onion root growth was increased by PEF and BFI treatments at an early growth stage, 60 DAT, with the most remarkable stem extension observed for PEF and BFI treatments after 150 DAT. PEF and BFI treatments increased the bulb's diameter, length, weight, and lodging at 180 DAT. BFI treatments exhibited a high portion of the "very large" category producing with 55.3 tons ha^-1 based on the classification into bulb size, followed by PE (49.3 tons), NM (9.4 tons), and BFII treatments (2.7 tons) at 230 DAT.

• Bulletin of the Korean Chemical Society
• /
• v.32 no.11
• /
• pp.4005-4010
• /
• 2011

We investigated thermal behavior of spin-coated films of P(HB-co-HHx)/PEG blends by using infraredreflection absorption (IRRAS) spectroscopy and 2D correlation spectroscopy. Based on 2D IRRAS correlation spectra, we could determine the sequence of spectral intensity changes with increasing temperature that PEG band changes first and then a band for crystalline component of P(HB-co-HHx) changes before a band for amorphous component. The intensities of bands for PEG and amorphous P(HB-co-HHx) were changed greatly as PEG weigh % of P(HB-co-HHx)/PEG blends increased. Transition temperatures of P(HB-co-HHx)/PEG blends were successfully determined by 2D gradient mapping method. The transition temperature of spincoated films of 98/2 and 90/10 P(HB-co-HHx)/PEG blends and 80/20 P(HB-co-HHx)/PEG blend determined by 2D gradient map are, respectively, about 137.5 and $132.5^{\circ}C$. Furthermore, P(HB-co-HHx)/PEG blends show an additional transition temperature that have been interpreted in terms of different lamellar thicknesses in spin coated films.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
• /
• v.29 no.1
• /
• pp.9-14
• /
• 2023

The application of starch-based films is limited by the poor water vapor barrier and mechanical properties. In this study, plasticized octenyl-succinated corn starch (OTPS) was mixed into Poly (butylene adipate-co-terephthalate) (PBAT) with various concentration (0/0.25/0.5/0.75 wt%) of epoxidized soybean oil (ESO) to enhance the mechanical properties and the hydrophobicity of blends. Tensile Strength and elongation at break of PBAT/OTPS film was slightly strengthened as the added ratio of ESO raised to 0.5 wt%, yet lessened again in 0.75 wt% sample. The yield strength and elastic modulus were highest in 0.25wt% of ESO added. In thermal properties, the melting temperature (T_m) and crystallization temperature (T_c) were highest at ESO 0.25 and the maximum degradation temperature (T_max) of components of the films were developed as ESO added. Also, it has been proved that the addition of hydrophobic substances reduces the hydrophilicity of the film by contact angle. This suggests the use of epoxidized oil for preparing films based on high TPS content allows obtaining enhanced interfacial adhesion. This study confirmed that ESO acts as a compatibilizer between OTPS and PBAT to improve the mechanical properties and hydrophobicity of the sample. The sample containing 0.5wt% of ESO was the most suitable for packaging application.

• Macromolecular Research
• /
• v.10 no.2
• /
• pp.54-59
• /
• 2002

ABA triblock copolymers of L-lactide and trimethylene carbonate with several different compositions were prepared by sequential ring-opening polymerization in the presence of diethylene glycol. Also chain-extension reactions of the resulting copolymers were carried out using hexamethylene diisocyanate to produce relatively high molecular weight polymers, which could be cast into elastomeric tough films. The polymers with certain L-lactide contents were partially crystalline, exhibiting two-phase morphology. The polymer films showed reversible elastic behavior under tensile tension, providing a novel thermoplastic elastomer possessing desirable properties such as biodegradability and good mechanical properties.

• Journal of Environmental Science International
• /
• v.19 no.9
• /
• pp.1161-1167
• /
• 2010

The effects of addition of non degradable polymers, polystyrene (PS) and poly(methyl methacrylate) (PMMA) on the rate of enzymatic degradation of biodegradable poly(l-lactide) (PLLA) have been studied in term of surface structure. Since a component in multicomponent polymeric system has shown surface enrichment, PS and PMMA which have lower surface energy than PLLA were selected as a minor blend component (5 wt%). Enzymatic degradation was carried out at $37^{\circ}C$ and pH 8.5 in the aqueous solution of Proteinase K. Two blend systems, partially miscible (PS/PLLA) and immiscible (PMMA/PLLA), showed the surface enrichment of 4 and 2 times of PS and PMMA, respectively. From the weight loss profile data, the slow degradation rate of both blend films was observed. This indicates that PS or PMMA domains which exist at surface act as a retardant of enzymatic attack.

• Composites Research
• /
• v.35 no.6
• /
• pp.419-424
• /
• 2022

Using non-biodegradable polymers is a severe environmental problem as they are not recyclable and generate a large amount of waste. Biopolymers, such as starch-based composites, have been considered one of the most promising replacement materials. These eco-friendly materials have the advantage of being low-cost, biodegradable, and obtained from renewable sources. However, as starch tends to be brittle and hydrophilic, it can make these materials unusable when exposed to water and limit its processability for further applications. In this work, a biobased modified starch was grafted using two bioderived materials, lauryl methacrylate (LMA) and tetrahydrofurfuryl methacrylate (THFMA), by radical polymerization. A polylactic acid (PLA) composite based on the modified starch (m-St) was fabricated to enhance its toughness. These samples were characterized by Fourier transform infrared, ¹H NMR and ¹³C NMR analysis, optical and scanning electron microscopy. The starch was successfully grafted, thus improving the compatibility with the PLA matrix. The mechanical properties of these films were also studied. Results from mechanical tests showed a slight enhancement of the mechanical performance of these composites when m-St was added to the PLA matrix. Such behavior is related to the improved dispersion of m-St 1:2 on PLA, confirmed by SEM images showing enhanced compatibility between modified starch and PLA matrix. This indicated excellent properties of the produced composite film for further eco-friendly applications.

• Korean Journal of Food Science and Technology
• /
• v.47 no.2
• /
• pp.224-232
• /
• 2015

The effects of cold plasma (CP) treatments on the physicochemical and biodegradable properties of a corn biomass-containing polyester (CBPE) film were studied. The CBPE film was treated with CP generated by $N_2$, $O_2$, He, Ar, or dry air at 400-900 W and 667 Pa for 10-40 min. The glass transition temperature of the CBPE film ($-30.2--28.6^{\circ}C$) was not affected by the CP treatment, while the elastic modulus and water vapor permeability decreased (p<0.05). The ink printability was improved by the treatment and the improved printability was maintained during storage for 56 days at room temperature. Roughness of the film increased after treatments and the level of roughness appeared to increase during storage. Heat and microbial biodegradability of the CBPE film was improved by the air-CP treatment (p<0.05). These results have demonstrated the potential of applying CP treatments to improve the flexibility, printability, and biodegradability of CBPE films.

• Macromolecular Research
• /
• v.9 no.4
• /
• pp.210-219
• /
• 2001

Quenched and slow cooled as well as isothermally crystallized poly(tetramethylene succinate)(PTMS) films at two different temperatures were prepared. In the process of hydrolysis of the four specimens, structural changes such as the crystallinity, crystal size distribution, lattice parameter, lamellar thickness, long period and surface morphology were investigated by using wide and small angle X-ray scattering (WAXS and SAXS), differential scanning calorimetry (DSC) and scanning electron microscopy (SEM). The hydrolytic degradation of quenched film was faster than that of slow cooled and isothermally crystallized films. The film crystallized at 100$\^{C}$ exhibited extensive micro voids and thus showed faster degradation than that crystallized at 75$\^{C}$, demonstrating surface morphology is another important factor to govern degradation rate. The crystallinity of the specimen increased by 5-10% and long period decreased after hydrolysis for 20 days. At the initial stage of degradation, the lamellar thickness of quenched film rather increased, while that of slow cooled and isothermally crystallized films decreased. The hydrolytic degradation preferentially occurred in the amorphous region. The hydrolytic degradation in crystal lamellae are mainly at the crystal surfaces.

• Bulletin of the Korean Chemical Society
• /
• v.32 no.3
• /
• pp.927-933
• /
• 2011

Conducting polyaniline-poly($\varepsilon$-caprolactone) polymer composites were synthesized via in situ deposition techniques. By dissolving different weight percentages of poly($\varepsilon$-caprolactone) (PCL) (10%, 20%, 30%, 40%, and 50%), the oxidative polymerization of aniline was achieved using ammonium persulfate as an oxidant. FTIR, UV-vis spectra, and X-ray diffraction studies support a strong interaction between polyaniline (PANI) and PCL. Structural morphology of the PANI-PCL polymer composites was studied using scanned electron microscopy (SEM) and transmittance electron microscopy (TEM), and thermal stability was analyzed by thermogravimetric analysis (TGA) technique. The temperature-dependent DC conductivity of PANI-PCL polymer composite films was studied in the range of 305-475 K, which revealed a semiconducting behavior in the transport properties of the polymer films. Conductivity increased with the increase of PCL in below critical level, however conductivity of the polymer film was decreased with increase of PCL concentration higher than the critical value.