Poly(propylene carbonate)/poly(3‐hydroxybutyrate)‐based bionanocomposites reinforced with cellulose nanocrystal for potential application as a packaging material

Tailoring graphitized cellulose nanocrystal morphologies for robust barrier and mechanical enhancement of PPC composites for green active packaging

Both nanocellulose and graphene nanosheets serve as exceptional fillers for biopolymers. However, there are limited materials that effectively combine the properties of these two fillers in Poly (propylene carbonate) (PPC) to enhance their overall properties. This study presents a meticulous approach to producing graphitized nanocellulose (GCNC) with tailored rod-like (R-GCNC) and spheres-like (S-GCNC) under low-temperature and ambient-pressure conditions. The formation and integration of the reinforcement network within the PPC matrix were compared by modulating these morphologies. The R-GC3%, with its stronger hydrogen bonding interactions, achieved a more optimal combination of properties than S-GC3%. Significantly, R-GCNC and PPC formed a robust reinforcement network, resulting in remarkable reductions of approximately 153 % in water absorption and 1669 % in water vapor permeability. Significantly, the mechanical properties of PPC were improved by 95 % in tensile strength and 1038 % in Young's modulus due to improved dispersion of R-GCNC with higher aspect ratio. In addition, R-GC3% had the highest glass transition temperature of 35.1 °C, and a maximum degradation temperature increased by 16.5 °C. The PPC/GCNC composites exhibited outstanding UV shielding, antioxidant properties, and rapid degradation rates. This study introduces a practical method for choosing suitable GCNCs as reinforcing agents to produce innovative green materials for the active packaging.

How surface modification of cellulose nanocrystals affects the crystallization process of poly (β-hydroxybutyrate)

Hydroxyl groups on the surface of cellulose nanocrystals (CNC) are modified by chemical methods, CNC and the modified CNC are used as fillers to prepare PHB/cellulose nanocomposites. The absorption peak of carbonyl group of the modified CNC (CNC-CL and CNC-LA) appears in the FT-IR spectra, which proves that the modifications are successful. Thermal stability of CNC-CL and CNC-LA is better than that of pure CNC. Pure CNC is beneficial to the nucleation of PHB, while CNC-CL and CNC-LA inhibit the nucleation of PHB. The spherulite size of PHB and its nanocomposites increases linearly over time, and the maximum growth rate of PHB spherulite exists at 90 °C. Rheological analysis shows that viscous deformation plays the dominant role in PHB, PHBC and PHBC-CL samples, while the elastic deformation is dominant in PHBC-LA. According to the rheological data, the dispersion of CNC-CL and CNC-LA in PHB is better than that of CNC. This work demonstrates the impact of modified CNC on the crystallization and viscoelastic properties of PHB. Moreover, the interface enhancement effect of modified CNC on PHB/CNC nanomaterials is revealed from the crystallization and rheology perspectives.

Improvement of properties of polylactic acid/polypropylene carbonate blends using epoxy soybean oil as an efficient compatibilizer

Epoxidized soybean oil (ESO) was used as a compatibilizer and blended with polylactic acid (PLA) and polypropylene carbonate (PPC) resin to prepare a series of PLA/PPC/ESO blends with varying compositions. The influence of the variation in the amount of ESO added to the blend system on the thermal properties, optical properties, rheological properties, mechanical properties, and microscopic morphology of the blends was studied. The research indicates that ESO can react with PLA and PPC to form a chemical bond interface, which improves the compatibility of PLA and PPC to a certain extent. With the increase in the amount of ESO added to the blend (1- 5 phr), the complete decomposition temperature, storage modulus, loss modulus, complex viscosity, notched impact strength, and elongation at break of the blend all show a trend of continuous increase. At the same time, the melt flow rate, light transmittance, and tensile strength of the blend do not show significant fluctuations. When the amount of ESO in the system is 5 phr, compared with the PLA/PPC blend, the notched impact strength and elongation at break of the PLA/PPC/ESO blend increase from 4270.3 J/m2, 43.89 % to 8560.4 J/m2, 211.28 %, respectively, and its tensile strength and transmittance still remain around 63 MPa, 92 %. This improves the toughness of the blend while maintaining its rigidity, demonstrating excellent mechanical and optical properties. At this time, the microscopic morphology of the fracture surface of the impact sample also shows obvious characteristics of tough fracture. However, when the amount of ESO added to the blend is excessive (6 phr), the compatibility of the blending system decreases, which will degrade the performance of the blending material and ultimately destroy the phase morphology of the blend and reduce its mechanical properties.

Graphene oxide as a multi-functional additive for compatilizer, enhancer, and barrier in ethylene vinyl alcohol copolymer/aramid pulp composites

To improve the thermal, mechanical, and barrier properties of ethylene vinyl alcohol copolymer (EVOH)/aramid pulp (AP), graphene oxide (GO) was used as a compatilizer, enhancer, and barrier to fabricate EVOH-based composites. The results showed that graphene oxide serves as an ideal compatilizer to reinforce the interfacial action between the EVOH matrix and aramid pulp. The EVOH/AP/GO composite presented the best combination of thermal stability, tensile strength, oxygen barrier, and heat deformation temperature by adding only 1 wt% graphene oxide, compared to those of pure EVOH. Moreover, both scanning electron microscopy (SEM) and polarized optical microscopy (POM) photographs demonstrated that the aramid pulp dispersed homogeneously into the EVOH resin with the addition of 1 wt% graphene oxide. Our work provides a novel and facile way for producing a prominent EVOH-based composite, which can be potentially used in packaging fields in the future.

Source of Nanocellulose and Its Application in Nanocomposite Packaging Material: A Review

Food packaging nowadays is not only essential to preserve food from being contaminated and damaged, but also to comply with science develop and technology advances. New functional packaging materials with degradable features will become a hot spot in the future. By far, plastic is the most common packaging material, but plastic waste has caused immeasurable damage to the environment. Cellulose known as a kind of material with large output, wide range sources, and biodegradable features has gotten more and more attention. Cellulose-based materials possess better degradability compared with traditional packaging materials. With such advantages above, cellulose was gradually introduced into packaging field. It is vital to make packaging materials achieve protection, storage, transportation, market, and other functions in the circulation process. In addition, it satisfied the practical value such as convenient sale and environmental protection, reduced cost and maximized sales profit. This review introduces the cellulose resource and its application in composite packaging materials, antibacterial active packaging materials, and intelligent packaging materials. Subsequently, sustainable packaging and its improvement for packaging applications were introduced. Finally, the future challenges and possible solution were provided for future development of cellulose-based composite packaging materials.

Atomization of Microfibrillated Cellulose and Its Incorporation into Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) by Reactive Extrusion

The present study focuses on the preparation and characterization of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) films that were reinforced with cellulose microstructures to obtain new green composite materials for sustainable food packaging applications. The atomization of suspensions of microfibrillated cellulose (MFC) successfully allowed the formation of ultrathin cellulose structures of nearly 3 µm that were, thereafter, melt-mixed at 2.5, 5, and 10 wt % with PHBV and subsequently processed into films by thermo-compression. The most optimal results were attained for the intermediate MFC content of 5 wt %, however, the cellulose microstructures showed a low interfacial adhesion with the biopolyester matrix. Thus, two reactive compatibilizers were explored in order to improve the properties of the green composites, namely the multi-functional epoxy-based styrene-acrylic oligomer (ESAO) and the combination of triglycidyl isocyanurate (TGIC) with dicumyl peroxide (DCP). The chemical, optical, morphological, thermal, mechanical, and barrier properties against water and aroma vapors and oxygen were analyzed in order to determine the potential application of these green composite films in food packaging. The results showed that the incorporation of MFC yielded contact transparent films, whereas the reactive extrusion with TGIC and DCP led to green composites with enhanced thermal stability, mechanical strength and ductility, and barrier performance to aroma vapor and oxygen. In particular, this compatibilized green composite film was thermally stable up to ~280 °C, whereas it showed an elastic modulus (E) of above 3 GPa and a deformation at break (ɛb) of 1.4%. Moreover, compared with neat PHBV, its barrier performance to limonene vapor and oxygen was nearly improved by nine and two times, respectively.

Preparation and applications of chitosan and cellulose composite materials

Chitosan is a natural fiber, chemically cellulose-like biopolymer, which is processed from chitin. Its use as a natural polymer is getting more attention because it is non-toxic, renewable, and biocompatible. However, its poor mechanical and thermal strength, particle size, and surface area restrict its industrial use. Consequently, to improve these properties, cellulose and/or inorganic nanoparticles have been used. This review discusses the recent progress of chitosan and cellulose composite materials, their preparation, and their applications in different industrial sectors. It also discusses the modification of chitosan and cellulose composite materials to allow their use on a large scale. Finally, the recent development of chitosan composite materials for drug delivery, food packaging, protective coatings, and wastewater treatment are discussed. The challenges and perspectives for future research are also considered. This review suggests that chitosan and cellulose nano-composite are promising, low-cost products for environmental remediation involving a simple production process.

Green Composites from a Bioplastic Blend of Poly(3-hyroxybutyrate-co-3-hydroxyvalerate) and Carbon Dioxide-Derived Poly(propylene carbonate) and Filled with a Corn Ethanol-Industry Co-product

Sustainable green composites were engineered from distillers' dried grains with solubles (DDGS), a co-product from the corn ethanol industry as a sustainable filler in bioplastic matrices made from a carbon dioxide-derived poly(propylene carbonate) (PPC) and poly(3-hyroxybutyrate-co-3-hydroxyvalerate) (PHBV) blend. The effect of water-washed DDGS (15 and 25 wt %) on the properties of injection-molded green composites from PHBV/PPC blends (60/40) and (40/60) and DDGS without and with peroxide (0.5 phr) has been investigated. From the results, it was noticed that the glass transition temperature (T _g) of the PHBV/PPC (60/40) bioplastic matrix increased by ∼9.6 °C by adding a peroxide cross-linking agent, indicating significant interaction (linkage) between PHBV and PPC polymers in this particular composition ratio, which was supported by SEM analysis as no phase separation was observed between PHBV and PPC. The tensile modulus of PHBV/PPC (60/40) and PHBV/PPC (40/60) blends with peroxide was improved by ∼40.7 and 1.5% after the addition of 25 wt % DDGS, respectively, due to its fibrous flaky structure. The % elongation values at break of the PHBV/PPC (60/40) blend matrices with and without peroxide were drastically improved by 18.5 and 90.7 folds, respectively, as compared to that of brittle pristine PHBV.