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Author: search.filters.author.Jianprasert, Apichaya

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    Photocrosslinked Poly(Vinyl Alcohol)–Tung Oil–Natural Rubber Films: A Sustainable Solution for Enhanced Water Resistance and Mechanical Properties in Biodegradable Packaging
    (2025-06-20)
    Monvisade, Pathavuth
    ;
    Jianprasert, Apichaya
    ;
    Sintoppun, Tanaporn
    ;
    Yamaguchi, Masayuki
    ;
    Rukchonlatee, Suparat
    This study introduces a novel approach to addressing the water resistance limitations of poly(vinyl alcohol) (PVA)-based biodegradable films by developing a ternary blend system incorporating tung oil (T) and natural rubber (R), forming PTR films. Photocrosslinking, combined with thermal and redox catalytic systems, facilitated the creation of enhanced network structures, as confirmed by FTIR analysis, particularly at tung oils conjugated double bonds. Dynamic mechanical analysis (DMA) revealed significant shifts in glass transition temperatures (T<inf>g</inf>), signifying enhanced crosslink density and interconnectivity between the components. The resulting PTR films demonstrated remarkable improvements in water resistance, evidenced by higher solid remain percentages, reduced water absorption, and significantly lower water vapor permeability (WVP). Mechanical properties, including tensile strength and Youngs modulus, improved by up to 150% (from 6.6 MPa of PT0R15-r-np to 16.3 MPa of PT0R15-r-p30) and 870% (from 6.6 MPa of PT0R15-r-np to 16.3 MPa of PT0R15-r-p30), respectively, due to the formation of robust network structures. Contact angle measurements and reduced moisture content further underscored the enhanced hydrophobic and moisture barrier properties. These findings establish photocrosslinked PTR films as a sustainable and high-performance option for biodegradable packaging applications, offering practical advantages such as reduced processing temperatures and production times.
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    Study on Crosslinked Structure and Thermal Properties of Polymer Networks Based on Tung Oil and PVA with Different Catalytic Systems
    (2017-04-01)
    Jianprasert, Apichaya
    ;
    Monvisade, Pathavuth
    ;
    Yamaguchi, Masayuki
    This work focuses on the effect of different catalytic systems on network structures and thermal properties of the polymer networks from poly(vinyl alcohol) (PVA) and Tung oil. The polymer networks based on Tung oil and PVA using potassium persulfate (KPS) as a thermal catalyst or KPS and sodium thiosulfate as a redox catalyst were performed at 60 °C and 80 °C. FTIR results confirmed that Tung oil could be crosslinked by both catalysts. Moreover, at 60 °C, it can be seen that the crosslinking reaction with the redox catalyst could occur better than with the thermal catalyst. To prove the crosslinking reaction of PVA in the polymer networks, water resistance of the polymer networks was also investigated. It was found that the PVA was successfully crosslinked by thermal catalyst but was not by redox catalyst. Besides, from this result, it could be suggested that, in the redox system, structure of the polymer networks was mainly formed by Tung oil. From DMA results, T<inf>g</inf> of PVA with the thermal catalyst is higher than that with the redox catalyst because of the network formation of PVA in thermal catalytic system. While the T<inf>g</inf> of Tung oil in the polymer networks with the redox catalyst is higher than that with the thermal catalyst. This is reasonable because the crosslinking reaction of Tung oil with the redox catalyst could easily occur better than with the thermal catalyst. Altogether, crosslink structure of Tung oil exhibited major influence on properties of PVA/Tung oil polymer network.
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    Surface improvement on water and oil affinities and absorption rate of PVA/Tung oil-coated paperboard and fiberboard
    (2016-03-01)
    Jianprasert, Apichaya
    ;
    Monvisade, Pathavuth
    ;
    Yamaguchi, Masayuki
    A novel coating material on paperboard and fiberboard from poly(vinyl alcohol) (PVA) modified with Tung oil was developed. The PVA/Tung oil coating was cured at several conditions: 25, 40, 50, and 60°C, in the presence of two types of catalysts, i.e., thermal catalyst using potassium persulfate (KPS) and redox catalyst using KPS and sodium thiosulfate. The chemical crosslinked structure of PVA/Tung oil-coating films was confirmed by FTIR. The result indicated the decrease in the double bonds of Tung oil by crosslinking reaction, especially at 60°C. In comparison with the same curing temperature, the films with redox catalyst showed more reduction in the number of double bonds of Tung oil. DMA results of the PVA/Tung oil-coating materials with redox catalyst showed the lowering of the heights of both β transition peak of Tung oil and α transition peak of PVA. FTIR and DMA results confirmed the more efficient crosslinking reaction of redox catalytic system than that of the thermal catalytic system. The water resistance and mechanical properties of these coating materials exhibited better values as projected to higher curing temperature and redox catalyst. SEM images showed the smooth surface of PVA/Tung oil covered on the paperboards with ~72 µm in thickness. The contact angle of water or oil drop and dynamic change in contact angle on the surfaces of PVA/Tung oil-coated paperboards and fiberboards were investigated. The results show the contact angles for both water and oil were lower than those of the uncoated ones, indicating the improvement of water and oil affinities of the PVA/Tung oil-coating materials. The dynamic changes in contact angle of the coated ones also decreased, suggesting the reduction in water and oil absorption rates of these coated substrates.
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    Combination of Tung oil and natural rubber latex in PVA as water based coatings for paperboard application
    (2015-11-04)
    Jianprasert, Apichaya
    ;
    Monvisade, Pathavuth
    ;
    Yamaguchi, Masayuki
    This research is focused on the preparation of the PVA/TO/NRL coatings for paperboard by using poly(vinyl alcohol) (PVA) as substance and blending with Tung oil (TO) and/or natural rubber latex (NRL) in order to enhance water resistance and dynamic mechanical properties. The effects of TO: NRL ratios on the structures were investigated by water resistance property and dynamic mechanical thermal analysis (DMA). The results showed that the water resistance property was improved by crosslinking of TO and film forming of NRL. The PVA/TO/NRL coating containing both TO and NRL gave better thermal behavior than those with only TO or NRL. For paperboard application, the PVA/TO/NRL coatings were applied on the paperboard to study water affinity and absorption rate on the coated surface. The rate of contact angle change of water on coated paperboards decreased depending on the ratios of TO and NRL.
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    Calcium silicate/poly(ethylene terephthalate) biomaterials via ring-opening polymerization
    (2012-10-01)
    Suebwongnat, Suebpong
    ;
    Jianprasert, Apichaya
    ;
    Siriphannon, Punnama
    ;
    Monvisade, Pathavuth
    Calcium silicate/poly(ethylene terephthalate) (CS/PET) composites were synthesized via ring-opening polymerization (ROP). CS raw material was synthesized by coprecipitation of calcium nitrate tetrahydrate and tetraethyl orthosilicate. Commercial grade PET was cyclodepolymerized under high dilution technique to cyclic oligo(ethylene terephthalate) (C-OET) raw material. The CS/PET precomposites were prepared by mixing 60:40 (C6P4) and 50:50 (C5P5) wt% of CS powder and C-OET with the presence of 3 mol% of dibutyl tinoxide catalyst (with respect to the cyclic) then shaped the pre-composites into cylindrical pellets. The presented C-OET in the pre-composites was ring-opening polymerized to obtain PET film covering on the CS grains with the different reaction temperatures as 180, 200 and 250 °C under vacuum for 24 h. Thermogravimetric analysis indicated that the ROP-PET content in the C5P5 and C6P4 composites were about 46-48 and 35-38 wt%, respectively. The melting points (T<inf>m</inf>) of ROP-PET of all composites were in a range of 233-246 °C. Compressive strength of the CS/ PET composites was significantly increased from 4.8 MPa of the neat CS to 31.0 MPa for the C5P5 composites at the ROP temperature of 250 °C. The CS/PET composites faster induced the continuous-phase formation of hydroxyapatite (HAp) nanocrystals on their surfaces than the HAp/polymer composites. The induction occurred within 7-day soaked in the simulated body fluid (SBF) solution, indicating the bioactivity of the CS/PET composites. © 2012 Springer Science+Business Media Dordrecht.