Properties and Degradability of Poly(Butylene Adipate-Co-Terephthalate)/Calcium Carbonate Films Modified by Polyethylene Glycol

Poly(butylene adipate-co-terephthalate) (PBAT) is a biodegradable polymer synthesized from petrochemical resources. PBAT has an exceptionally high elongation at break values which makes it one of the most promising substitutes for LDPE packaging films. However, the applicability of PBAT films is still limited by low strength and high production costs. In this work, we used polyethylene glycol 600 (PEG-600) as a coating agent to modify the surface of calcium carbonate and improve compatibility with the polymer matrix. A series of PBAT/CaCO₃ composite films having different CaCO₃ particle size and content of coating agent was prepared using extrusion blow molding. The effect of particle size of CaCO₃ filler and the content of a coating agent on the mechanical and rheological properties of composite films have been studied. The biodegradation properties have been tested by burying the samples in soil or keeping them in artificial seawater for 90 days. It was shown that the addition of PEG-600 improves compatibility between the matrix and CaCO₃ filler as polar –OH groups of PEG have a high affinity toward the polar surface of CaCO₃. Moreover, the hydrophilicity of PEG-600 increased the diffusivity of water molecules and facilitated PBAT degradation. This work provides experimental data and theoretical guidance that support the development of high-performance PBAT/calcium carbonate films for the single use packaging industry.

Preparation and Evaluation of Rice Bran-Modified Urea Formaldehyde as Environmental Friendly Wood Adhesive

In this study, defatted rice bran (RB) is used to prepare an environmentally friendly adhesive through chemical modifications. The RB is mixed with distilled water with ratios of 1:5 and 1:4 to prepare Type A and Type B adhesives, respectively having pH of 6, 8 and 10. Type A adhesive is prepared by treating RB with 1% potassium permanganate and 4% poly(vinyl alcohol), whereas Type B is formulated by adding 17.3% formaldehyde and 5.7% urea to RB. Viscosity, gel time, solid content, shear strength, Fourier transform infrared (FTIR) spectroscopy is carried out, and glass transition temperature (T g), and activation energy (E a) are determined to evaluate the performance of the adhesives. E a data reveal that adhesives prepared at mild alkaline (pH 8) form long-chain polymers. Gel time is higher in the fabricated adhesives than that of the commercial urea formaldehyde (UF). FTIR data suggest that functional groups of the raw RB are chemically modified, which enhances the bondability of the adhesives. Shear strength data indicates that bonding strength increases with increasing pH. Similar results are also observed for physical and mechanical properties of fabricated particleboards with the adhesives. The results demonstrate that RB-based adhesives can be used as a potential alternative to currently used UF-based resin.

Enhancement of the interfacial interaction between poly(vinyl chloride) and zinc oxide modified reduced graphene oxide

ZnO nanoparticles acted as a ‘bridge’, connecting with PVC chains and rGO sheets, to enhance the interfacial strength between them.

Synthesis of PVC/CNT nanocomposite fibers using a simple deposition technique for the application of Alizarin Red S (ARS) removal

A novel deposition route for PVC/CNT nanocomposite fibers synthesis and its application towards ARS removal.

Wood plastic composite using graphene nanoplatelets

This article presents the preparation and characterization of wood flour/polypropylene (PP) composites filled with graphene nanoplatelets (GNPs). The effects of GNPs, as reinforcing agent, on the mechanical and physical properties were also investigated. In order to increase the interphase adhesion, maleic anhydride grafted polypropylene (MAPP) was added as a coupling agent to all the composites studied. The morphology of the specimens was characterized using scanning electron microscopy (SEM) technique. The results of strength measurements indicated that when 0.8 wt.% GNPs were added, tensile and flexural properties reached their maximum values. At high levels of GNPs loading (3-5 wt.%), increased population of GNPs leads to agglomeration and stress transfer gets blocked. The addition of GNPs filler moderately increased the impact strength of composites. Addition of GNPs decreased the average water uptake and thickness swelling by 35% and 30%, respectively, compared to the control sample (without GNPs). It was observed that the composites filled with GNPs decomposed at higher temperatures compared to the pure PP and control. In all cases, the degradation temperatures shifted to higher values after the addition of GNPs. The improvement of physical and mechanical properties of composites confirmed that GNPs have good reinforcement and the optimum effect of GNPs was achieved at 0.8 wt.%.