Photoadhesives have been beneficial for a plethora of applications due to advantages in spatiotemporal control, flexible operating temperature, and in situ applicability. As a sustainable approach, bio-based precursors have been applied for the production of photoadhesives. However, the use of toxic chemicals and incorporation of petroleum-based chemicals in the synthesis process is inevitable. In this study, a photocurable itaconic acid-based polyester, poly(1,3-propanediol-co-citrate-co-itaconate-co-1,12-dodecanedioate) (IAP), was developed from bio-based precursors through a facile, catalyst-free, and solvent-free polycondensation process without use of toxic chemicals. Ultraviolet (UV)-triggered photocross-linking in the presence of a photoinitiator was found to induce adhesion capability in IAP. With 30 min of UV exposure, IAP presented an adhesion strength of 1286.0 ± 19.2 kPa against acrylic substrates. Remarkable adhesion strengths to stainless steel, wood, glass, and polytetrafluoroethylene substrates were also achieved. Due to photo-induced reduction in hydrophilicity of IAP, the polymer was able to repel water at the adhesive−substrate interface upon in situ underwater photocuring, leading to successful wet adhesion. Subsequently, excellent photo-adhesion was also obtained from in situ photocuring of IAP in seawater, simulated body fluid, and silicon oil. This study provides insights into the development of a photo-enhanced and versatile adhesive through green engineering.
Plastic pollution is a significant concern nowadays due to wastes generated from non-biodegradable and non-renewable synthetic materials. In particular, most plastic food packaging material ends up in landfills, creating mass wastes that clog the drainage system and pollute the ocean. Thus, studies on various biopolymers have been promoted to replace synthetic polymers in food packaging and consequently, the high number of research in biopolymers food packaging, especially in the characterization, properties and also the development of the biopolymer. For biopolymer-based food packaging, silk fibroin (SF) has been highlighted because of its biodegradability and low water vapor permeability properties. This review focuses on the different properties of SF films prepared through solution casting and electrospinning for food packaging. Discussions encompassed chemical properties, mechanical properties, permeability, and biodegradability. This review also discussed the studies that used SF as the biomaterial for food packaging.
Bombyx Mori fiber consists of two major proteins which are fibroin and sericin. The silk fibroin (SF) is the core structural protein of silk fiber. SF protein structures comprise of primary and secondary structures; where the primary structure contains series of amino acid and secondary structure with Silk I refers to the water-soluble and Silk II, high β sheet extent which is insoluble. This study was conducted to compare the structural and characterization of insoluble Thai Bombyx Mori SF with different types of post-treatement. Thai silk cocoons, which were degummed and dissolved in 9.3 M LiBr solution at 60 °C. The obtained SF solutions were dialyzed and purified. SF films were prepared by solution casting and immersing in methanol and ethanol, followed by water annealing in water saturated vacuum. Post-treatment was purposely done to regenerate and induce of the β sheet structure to enhance the insolubilities and the stabilities properties of the SF films. The SF films structural conformation, characterization and thermal stability were characterized. Attenuated total reflectance-Fourier transformed infrared spectroscopy (ATR-FTIR) showed that SF films were presented in a more stable form after ethanol post treatment, which also supporting by X-ray diffraction (XRD) analysis which indicated the tendency to higher structural organization. Thermal analysis resutls showed that SF was thermally stable and improved after post treatment. The contact angle of post treated SF increased the hydrophobicity of the films. The thai SF films could be the promising candidate for applications in tissue regeneration, optical devices, and flexible electronic displays with the possibility to control the SF structure and properties.
The influence of talc and poly (methyl methacrylate) (PMMA)-grafted (g)-talc on the mechanical properties of poly (vinyl chloride) (PVC) was investigated. The graft copolymerization was carried out under nitrogen atmosphere, using the free radical initiation technique. The blend formulations were first dry blended using a mixer before being milled into sheets on a two-roll mill at 165°C, and then hot pressed into composites at 190°C. The flexural modulus of both composites increased with increasing filler content from 0 to 20 part per hundred resin (phr), however the increment of grafted (57.7%) was higher than ungrafted composites (48.5%). A similar trend has also been observed for thermal stability. The impact strength of grafted was increased by 45.82%, whereas 18.96% in reduction was observed for the ungrafted composites. The decrement of flexural strength by 16.6% and 21.1% of grafted and ungrafted, respectively, has also shown the improvement in mechanical properties of grafted composites.
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