Effect of composition on permeability, mechanical properties and biodegradation of PBAT/PCL blends films

Fabrication and Characterization of Poly(hydroxybutyrate)- and Poly(caprolactone)-Based Active Biodegradable Films Incorporating Allyl Isothiocyanate

In this study, in order to overcome the fragility and cost disadvantages of PHB-based films, PHB was blended with PCL. Additionally, allyl isothiocyanate (AITC) was incorporated as an active component. The resulting PHB, PCL, and PHB/PCL composite films with/without allyl isothiocyanate (AITC) prepared via the casting method were analyzed for their physicochemical, thermal, mechanical, barrier, morphological properties and antimicrobial and antioxidant activities. While neat PHB films showed the highest tensile strength (TS) of 19.82 MPa and the lowest elongation at break (EB) of 1.13%, PHB/PCL blend films exhibited lower TS (15.34 MPa) and higher EB values (21.33%). AITC addition decreased TS significantly while showing no significant impact on EB. PHB/PCL blend films had the highest water vapor permeability (WVP) values, possibly due to their increased porosity, while neat PCL- and PHB-based films showed better oxygen and water vapor barrier properties, respectively. DSC analysis showed that PHB and PCL films had a crystalline phase, while in the case of PHB/PCL blend films, both polymers maintained their characteristic melting behaviors. The addition of AITC affected the thermal stability by increasing the melting temperature of the PHB films and decreasing the melting temperature of the PCL films. SEM analyses revealed that PHB and PHB-A films had a homogeneous structure, while irregular spherical structures and cracks were also observed in PCL and PCL-A films. The incorporation of AITC into the film samples (PHB-A, PCL-A, and PHB/PCL-A) brought remarkable antimicrobial (from 16.25 mm to 37.25 mm of inhibition zones) and antioxidant activity (from 281.85 to 286.41 mg trolox equivalent/1 g film sample, as measured by CUPRAC), while no activity was observed in the control films without AITC (PHB, PCL, and PHB/PCL). In conclusion, new AITC-activated PHB-, PCL-, and PHB/PCL-based films were successfully designated with additional functionalities and showed valuable potential to be used in active biodegradable food packaging applications.

Incorporation of Nano-Zinc Oxide as a Strategy to Improve the Barrier Properties of Biopolymer-Suberinic Acid Residues Films: A Preliminary Study

Finishing coatings in the wood-based composites industry not only influence the final appearance of the product but also serve to protect against fungi and molds and reduce the release of harmful substances, particularly formaldehyde and volatile organic compounds (VOCs). Carbon-rich materials, such as those derived from birch bark extraction, specifically suberin acids, can fulfill this role. Previous research has demonstrated that adding suberin acid residues (SAR) at 20% and 50% by weight significantly enhances the gas barrier properties of surface-finishing materials based on poly(lactide) (PLA) and polycaprolactone (PCL), particularly in terms of total VOC (TVOC) and formaldehyde emissions. This study aims to explore whether these properties can be further improved through the incorporation of nano-zinc oxide (nano-ZnO). Previous research has shown that these nanoparticles possess strong resistance to biological factors and can positively affect the characteristics of nanofilms applied as surface protection. The study employed PLA and PCL finishing layers blended with SAR powder at 10% w/w and included 2% and 4% nano-zinc oxide nanoparticles. The resulting blends were milled to create a powder, which was subsequently pressed into 1 mm-thick films. These films were then applied to raw particleboard surfaces. TVOC and formaldehyde emission tests were conducted. Additionally, the fungal resistance of the coated surfaces was assessed. The results showed that PLA/SAR and PCL/SAR composites with the addition of nano-zinc oxide nanoparticles exhibited significantly improved barrier properties, offering a promising avenue for developing biodegradable, formaldehyde-free coatings with enhanced features in the furniture industry. Furthermore, by utilizing SAR as a post-extraction residue, this project aligns perfectly with the concept of upcycling.

Poly(Butylene Adipate/Terephthalate-Co-Glycolate) Copolyester Synthesis Based on Methyl Glycolate with Improved Barrier Properties: From Synthesis to Structure-Property

The main problem of manufacturing with traditional biodegradable plastics is that it is more expensive than manufacturing with polymers derived from petroleum, and the application scope is currently limited due to poor comprehensive performance. In this study, a novel biodegradable poly(butylene adipic acid/terephthalate-co-glycolic acid) (PBATGA) copolyester with 25–60% glycolic acid units was successfully synthesized by esterification and polycondensation using cheap coal chemical byproduct methyl glycolate instead of expensive glycolic acid. The structure of the copolyester was characterized by ATR-FTIR, 1H NMR, DSC, and XRD; and its barrier property, water contact angle, heat resistance, and mechanical properties were tested. According to the experiment result, the PBATGA copolyesters showed improved oxygen (O2) and water vapor barrier character, and better hydrophilicity when compared with PBAT. The crystallization peaks of PBATGAs were elevated from 64 °C to 77 °C when the content of the GA unit was 25 mol %, meanwhile, the elongation at the break of PBATGA25 was more than 1300%. These results indicate that PBATGA copolyesters have good potentiality in high O2 and water vapor barrier and degradable packaging material.