Pure PPC Research Articles

The polytannic acid‐Fe(III) functionalized graphene oxide in poly (propylene carbonate) nanocomposite enabling enhanced shape memory, UV‐resistance, and self‐healing performance

AbstractPolypropylene carbonate (PPC) is a promising candidate of substrate materials used for human wearable devices due to its excellent ductility and biocompatibility. However, PPC is prone to be deformed, thus resulting in poor shape recovery property. One effective solution is to construct composites. In this work, poly (tannic acid) with Fe3+ (FPTA) @ graphene oxide (GO) was added to fabricate FPTA@GO/PPC composites. The results show that FPTA@GO can construct a tight network of hydrogen bonds into PPC to improve shape memory and self‐healing properties. By varying the FPTA@GO content, the composites exhibit tunable shape memory property. Dynamic mechanical analysis confirms that FPTA@GO/PPC composites show better shape memory properties compared with pure PPC. 5 wt% FPTA@GO/PPC composite demonstrates superior shape fixation ratio (Rf = 99%) as well as superior shape recovery ratio (Rr = 94%) in 37°C. Moreover, 5 wt% FPTA@GO/PPC composite possesses great self‐healing efficiency of 81% and tensile strength (17.2 MPa). The UV absorption capacity of 5 wt% FPTA@GO/PPC is increased by 150% (far and mid‐UV regions) and 400% (near‐UV region) compared with pure PPC. Thus, FPTA@GO/PPC composites have potential applications in developing shape memory, self‐healing, and UV‐resistant materials for human wearable devices.

Antioxidant and Biocompatible CO2‐Based Biocomposites from Vegetable Wastes for Active Food Packaging

AbstractIn this study, an innovative and scalable strategy is developed to valorize vegetable wastes as valuable and cost‐effective natural antioxidant resources in the development of CO2‐based biocomposites. The dried vegetable stems (parsley and spinach) are firstly micronized and then incorporated into a CO2‐derived poly(propylene carbonate) (PPC) polymer matrix by hot compression molding technique. The vegetable waste microparticles are found to be homogenously dispersed within the PPC matrix. Due to the establishment of a strong intermolecular hydrogen bond network between PPC and vegetable waste microparticles, the obtained biocomposites exhibit improved mechanical properties compared to pure PPC, comparable to these of common plastics use for packaging materials. The water barrier properties of the developed biocomposites are also promising for packaging applications. Additionally, the developed biocomposites are found to be biocompatible and show effective antioxidant scavenging activity against 2,2′‐azinobis(3‐ethylbenzothiazoline‐6‐sulfonic acid) radical cation (ABTS•+). Therefore, these antioxidant and biocompatible biocomposites deriving from CO2 greenhouse gas and industrial agro‐food wastes are of great interest for active food packaging applications.

High Strength and Barrier Properties of Biodegradable PPC/PBSA Blends Prepared by Reaction Compatibilization for Promising Application in Packaging

AbstractPoly(propylene carbonate) (PPC)/poly(butylene succinate‐co‐butylene adipate) (PBSA) blends are prepared via melt mixing using a twin‐screw extruder. A one‐step method based on the reaction compatibilization mechanism is used to prepare PPC/PBSA/AX8900(ethylene‐methyl acrylate‐glycidyl methacrylate random terpolymer) blends. The films of blends are prepared by an extrusion blown film machine. Fourier transform infrared spectroscopy results show that there is a strong hydrogen bonding between PPC and PBSA. The epoxy group of AX8900 can react with molecular chains of PPC and PBSA. It is shown from the rheological behavior that AX8900 can extend the molecular chains and increase the compatibility of PPC and PBSA. The films of PPC/PBSA blends exhibit more orientation structure than pure PPC film. The tensile strength of machine direction and transverse direction for 70PPC/30PBSA/1AX8900 film is higher than that for pure PPC film. The PPC/PBSA/AX8900 films have similar excellent barrier properties, compared with PPC film. The modified Maxwell theoretical model is used to predict and analyze changes in film barrier properties.

Poly(propylene carbonate)/clay nanocomposites with enhanced mechanical property, thermal stability and oxygen barrier property

To develop eco-polymeric materials is of significant importance to protect the global environment and promote the sustainable development of human society. Poly (propylene carbonate) (PPC) as a new biodegradable polymer has attracted much interest, but some properties of PPC have to be improved before the practical utilization.In this work, the re-dispersible unmodified laponite and montmorillonite (MMT) were used as the nanometer reinforcing phase to enhance the mechanical property, thermal stability and oxygen barrier property of PPC. Via a simple solution mixing method, the PPC/laponite and PPC/MMT nanocomposites were fabricated. The unmodified laponite and MMT were well dispersed in the PPC matrix, which was confirmed by TEM results. As a result, the obtained PPC/clay nanocomposites exhibited high transparency (>80%) and enhanced storage modulus (100–150% higher than PPC), when the clay content was in a range of 1–10 wt%. In addition, the incorporation of lower than 3 wt% of laponite and MMT increased the elongation at break and thermal stability of PPC. The initial decomposition temperature (Td10%) of PPC/clay nanocomposites with 1 wt% clay was approximately 250 °C, which was substantially higher than that of pure PPC (215 °C). The PPC/clay nanocomposites with 7 wt% clay displayed the lowest O2 permeability, which was two orders of magnitude lower than that of pure PPC. Therefore, the resultant PPC/clay nanocomposites with enhanced properties have a potential to boost the practical utilization of PPC.

Zeolitic Imidazolate Framework-8/Polypropylene-Polycarbonate Barklike Meltblown Fibrous Membranes by a Facile in Situ Growth Method for Efficient PM2.5 Capture.

Environmental pollution, especially air pollution, seriously endangers public health globally. Due to severe air pollution, air filters still face many challenges, especially in terms of filtration performance and filtration stability. Herein, a zeolitic imidazolate framework-8/polypropylene-polycarbonate barklike meltblown fibrous membrane (PPC/ZIF-8) was designed through meltblown and an in situ growth method, achieving efficient PM2.5 capture and high filtration stability under a harsh environment. After in situ growth, the PPC/ZIF-8 membrane could dramatically enhance the PM2.5 filtration efficiency without increasing the pressure drop; the PM2.5 filtration efficiency and quality factor were up to 32.83 and 116.86% higher than those of the pure PPC membrane, respectively. Moreover, through five filtration-wash-dry cycles, the PM2.5 filtration performance is still at a high level. This PPC/ZIF-8 membrane provides a new strategy for the preparation of an air filter with excellent comprehensive filtration performance.

Influence of Filler Loading on the Tensile Properties of Poly (Propylene Carbonate) Ligno-Cellulosic Particulate Filler Biocomposite Films

Biodegradable composite films were fabricated using poly(propylene carbonate) (PPC) and lignocellulosic coconut shell particle (CSP). The result of varying filler addition (5 to 25wt.%) on their tensile properties was investigated. The tensile strength of the composites was found to be inferior to the pure PPC matrix films however marginal improvement was noticed in case of the modulus. The stiffness of the composites enhanced until 20 wt.% of CSP and was comparable with the synthetic polymers used in the packaging applications. The features of fillers and their distribution within the matrix was analyzed using the SEM micrographs.

A Composite Solid Polymer Electrolyte Containing Poly(propylene Carbonate) and Li1.5Al0.5Ge1.5(PO4)3 for All-Solid-State Li-Ion Batteries

During last ~30 years, lithium-ion batteries (LIBs) have been improved significantly in aspects of energy density and cyclability. In spite of several advantages of LIBs, the conventional LIBs still have suffered from the issues related to organic based electrolytes, such as leakage, volatility, flammability, and lithium dendrite formation through porous separator leading to internal short circuits. A solution is to replace the organic liquid electrolyte with suitable composite solid polymer electrolyte (CSPE). Poly(ethylene oxide) (PEO) based electrolytes are the most studied solid polymer electrolyte (SPE). However, narrow potential window, poor mechanical strength, low lithium transference number, and insufficient ionic conductivity are the major issues to be addressed in case of PEO. In contrast, poly(propylene carbonate) (PPC) has attracted tremendous attention as an alternative owing to its higher ionic conductivity, better lithium transference number, and wide potential window. The weak mechanical strength of PPC membranes is the main bottle neck to be addressed before it sees the limelight of practical application. Incorporation of a ceramic filler into PPC polymer is one of the promising way to improve the ionic conductivity as well as the mechanical strength of SPE. Among the ceramic fillers, NASICON type Li1.5Al0.5Ge1.5(PO4)3 (LAGP) possesses good stability to moisture, thermal stability, and electrochemical stability. In this work, we have studied the effects of LAGP incorporation in PPC matrix on the physical and electrochemical properties of CSPE for all-solid-state LIBs. The formation of LAGP phase was analyzed by XRD, SEM, and TEM. Furthermore, the thermal stability of prepared CSPE was evaluated using DSC and TGA. The CSPE exhibited higher ionic conductivity and mechanical strength compared with pure PPC, leading to improvement in electrochemical properties of all-solid-state lithium ion batteries composed of Li/CSPE/LiNi0.6Co0.2Mn0.2O2 (NCM622).

Thermal, Mechanical Properties and Rheological Behavior of Poly(Propylene Carbonate)/Poly(Ethylene Glycol)/Graphene Oxide Nanocomposites

Graphene oxide (GO) is an efficient nanofiller for polymers and a good dispersion of GO in polymer matrix is most important to enhance properties. Poly(propylene carbonate) (PPC)/GO nanocomposite was prepared by a method with solution blending and melt mixing for improvement of GO dispersion. First, GO was prepared using an improved Hummers method. In the solution blending, GO was well dispersed in water and another low molecular weight polymer, poly(ethylene glycol) (PEG), was also dispersed in water, as a dispersion medium for next melt mixing of PPC and GO. Then PPC and PEG/GO was melt-mixed in a HAAKE mixer. The dispersion of GO in PPC matrix and effect of GO content on properties of PPC/PEG/GO nanocomposites was investigated. Results show that tensile strength of nanocomposites with the content of 0.5 wt% GO increased from 17.51 MPa (pure PPC) to 21.61 MPa and elongation at break can be kept high. The complex viscosity, storage and loss modulus is the highest for nanocomposites with the content of 0.5 wt% GO. This illustrated that a lower content of GO can improve the properties of PPC, owing to the good dispersion of GO in PPC matrix. Based on dispersion of GO and chemical structure of PPC, PEG, and GO, the reinforcement mechanism of GO in PPC was analyzed.

Mechanical reinforcement in poly(propylene carbonate) nanocomposites using double percolation networks by dual volume exclusions

Poly(propylene carbonate) (PPC) nanocomposites with poly(lactic acid) (PLA) and sepiolite nanofibers (NF) double percolation networks were prepared according to the dual volume exclusions principle. A two-step melt mixing with annealing process was adopted to construct the double percolation networks, which were verified by rheological and morphological characterization. The formation of double percolation networks structure effectively increased both the mechanical properties and heat resistance of PPC due to the greatly improved efficiency of the formation of force transferring network of NF. As a result, the PPC/PLA/NF ternary nanocomposites with double percolation networks exhibited elastic modulus about three orders higher than that of the pure PPC at 100 °C. The thermal deformation temperature, evaluated from the modulus at the glass transition of pure PPC (0.1 GPa), was found to be above 100 °C.

Design of the electrically conductive PHB blends for biomedical applications

Biopolymer blends consisting of insulating crystalline poly(3-hydroxybutyrate) (PHB)/Poly(propylene carbonate) (PPC)/multi-walled carbon nanotubes/plasticizer were prepared by solvent casting, then melted to form films with the hydraulic hot press. The miscibility, crystallization, morphology, thermal properties, and electrical properties were investigated by DSC, TGA, TEM, DC—and AC conductivity. The presence of MWCNT shows the important effect on dielectric and conductivity properties of PHB/PPC blends. The blend films show improved the electrical conductivity from 10−17 Scm−1 of the pure PHB film to 3 × 10−1 Scm−1 by increasing the concentration of MWCNTs for blend 4. The dielectric constant of (e′) of PHB blend has a maximum of between 40 and 200. It has increased ~ 50 orders than pure PHB and pure PPC. The activation energy for DC conduction is about 0.119–0.442 eV, which is typical of electronic conduction in blends 1, 2, and 3, it decreased with increasing the MWCNTs concentration in blend 4 and the conductivity believes like semiconductive behavior. TEM was found that the nanotubes are dispersed uniformly in the PHB matrix and the PHB chains wrap around the nanotube walls.

Enhanced Properties of Biodegradable Poly(Propylene Carbonate)/Polyvinyl Formal Blends by Melting Compounding.

Polyvinyl formal (PVF) was first synthesized via the reaction of poly(vinyl alcohol) (PVA) and formaldehyde. The synthesized PVF exhibits a high decomposition temperature, glass transition temperature, and low melting point compared to pristine PVA. The synthesized PVF can be melt processed at temperatures much lower than PVA. Poly(propylene carbonate) (PPC) and the as-made PVF were melt blended in a Haake mixer. The mechanical properties, thermal behaviors, and morphologies of PPC/PVF blends were investigated. Compared to the pure PPC, PPC/PVF blends show higher tensile strength and Vicat softening temperature. Thermogravimetric (TGA) result reveals that the thermal stabilities of PPC/PVF blends decreased with the increase of the content of PVF. Scanning electron microscopy (SEM) observation indicates that the interfacial compatibility of the PVF and PPC matrix is better than that of the PVA and PPC matrix. The PPC/PVF blends show much better comprehensive properties compared to pure commercial PPC, which provides a practical way to extend the application of PPC copolymer.

Sandwich-Like Poly(propylene carbonate)-Based Electrolyte for Ambient-Temperature Solid-State Lithium Ion Batteries

A poly(propylene carbonate) (PPC)-based sandwich-like composite solid polymer electrolyte (SE) was designed and applied to solid-state lithium ion batteries at 25 °C. The sandwich-like structure of the composite SE was composed of three parts. A polypropylene separator was used as a support membrane to enhance the strength of the SE membrane. Succinonitrile in the PPC-based SE was used to increase the ionic conductivity. Pure PPC as a buffer layer was closed to the lithium anode, which could improve the interface compatibility, Coulombic efficiency, and cycle life of batteries. The sandwich-like composite SE exhibited good comprehensive properties such as a high ion transference number (0.65), sufficient ionic conductivity (2.18 × 10–4 S cm–1 and 5.77 × 10–4 S cm–1 at 25 and 55 °C, respectively), and outstanding electrochemical stability at ambient temperature. Furthermore, a Li/LiFePO4 cell with the sandwich-like composite SE delivered a discharge capacity close to 140 mA h g–1 (0.1 C) at 25 °C. The resu...

A Novel Multiblock Copolymer of CO2-Based PPC-mb-PBS: From Simulation to Experiment

A kind of new biodegradable materials with high performance in a wide range of temperatures was effectively developed via the combination of theoretical calculations and experimental works. The new polymer of poly(propylene carbonate)-multiblock-poly(butylene succinate) (PPC-mb-PBS) was designed and synthesized from poly(propylene carbonate) (PPC) and poly(butylene succinate) (PBS) segments. The simulation was successfully performed based on their multiblock topology structure. On the basis of the calculation, the Tg of PPC-mb-PBS calculated by molecular dynamics (MD) simulation ranges from −42 to −38 °C that is independent of the block size of PPC segments. The end-to-end distance and mean square displacement (MSD) calculations indicate an inversion behavior of the PPC and PBS between hard and soft segments at different temperatures. The stress–strain behavior of PPC-mb-PBS was also calculated by the MD simulation of uniaxial deformation. The simulated stress of PPC-mb-PBS copolyesters is higher than that of pure PPC under uniaxial extension with the same strain and is found to increase with decreasing PPC block size. To verify the validity of the simulation, the PPC-mb-PBS multiblock copolyesters with various designed block length were synthesized and characterized by 1H NMR, DOSY, and GPC. Meantime, their thermal and mechanical properties were determined, respectively, by DSC and tensile testing. The measured Tg data and the variation tendency of tensile strength are in very good agreement with the simulated results, demonstrating the ability of the fully atomic-scale MD simulations to well predict the mechanical properties of the synthesized biodegradable polymers.

Poly (propylene carbonate)-based in situ nanofibrillar biocomposites with enhanced miscibility, dynamic mechanical properties, rheological behavior and extrusion foaming ability

Abstract Poly (propylene carbonate) (PPC) foams have attracted more attention in recent years because of their biodegradability and the fixation of carbon dioxide (CO 2 ). Despite their many attractive features, a relatively low decomposition temperature, a low glass transition temperature (T g ), weak mechanical properties and poor melt strength of PPC matrix limited their commercial applications as a viable candidate for conventional plastics. In this study, we report a facile, effective, low-cost and eco-friendly approach for the preparation of PPC/PBS/PTFE ternary in situ nano-fibrillar biocomposites to significantly improve the strength and foaming ability of PPC without sacrificing their excellent biodegradability. The in situ nano-fibrillar networks in the PPC/PBS matrix demonstrated that significant reinforcement effects on the matrix strength, dynamic mechanical and rheological properties at low PTFE contents. In contrast to pure PPC, T g increased by 15 °C, 851% higher in storage modulus and 17 times enhancement in the initial viscosity of biocomposites. In continues extrusion foaming process, the PBS domains and PTFE nano-fibrils network generated remarkable synergistic effects on the foaming behavior, resulted in higher cell densities (two orders of magnitude), compressive modulus (30 times) and compressive strength (20 times) of PPC/PBS/PTFE (70/30/3) biocomposites.

Biocompatible Shape Memory Blend for Self-Expandable Stents with Potential Biomedical Applications.

Biocompatible poly(propylene carbonate) (PPC)/polycaprolactone (PCL) shape memory blends were fabricated using melt blending. The shape memory performance of these blends was found to depend remarkably on their components. On addition of 25 vol % PCL, one blend (PL-25) achieved an optimal shape-fixing ratio (Rf) and -recovery ratio (Rr). Specifically, its Rr considerably increased by 24.1 and 50.0% compared with those of pure PPC and PCL, respectively, because of the restricted irreversible deformation of the amorphous chains cross-linked by tiny crystals. After undergoing three thermomechanical cycles, Rf and Rr reached 97.0%. The PL-25 blend was further melt-processed into a stent, which showed a fast response and self-expansion at 37 °C. These results, along with those obtained from evaluating the material's blood compatibility, in vitro degradation and drug release behavior, demonstrated the great potential of PL-25 for biomedical applications.

Effects of heat-treatment on surface morphologies, mechanical properties of nanofibrous poly(propylene carbonate) biocomposites and its cell culture

Abstract We report controlled surface morphologies, mechanical properties and cell culture of biomimetic pure poly(propylene carbonate) (PPC) and PPC/poly(lactic acid) (PLA) composite nanofibers prepared by sol–gel electrospinning. Pure PPC nanofibers exhibited soft rubber-like features with lower mechanical properties (elastic modulus ∼59.7 MPa, tensile strength ∼6.2 MPa), while the mechanical properties of as-spun PPC nanofibers were dramatically improved after heat-treatments at 60 °C. Furthermore, the PPC/PLA composite nanofibers exhibited topographically peculiar morphologies (in particular, an embossing-like surface protrusions), probably due to poor miscibility between PPC and PLA. CCK-8 assay results of cultured myoblasts clarified that pure PPC and PPC/PLA composite nanofibers were nontoxic to the cells, which therefore, suggest them to be used in biomedical applications as a scaffold for tissue engineering.

Biodegradable poly(propylene carbonate)/layered double hydroxide composite films with enhanced gas barrier and mechanical properties

Relatively well crystallized and high aspect ratio Mg-Al layered double hydroxides (LDHs) were prepared by coprecipitation process in aqueous solution and further rehydrated to an organic modified LDH (OLDH) in the presence of surfactant. The intercalated structure and high aspect ratio of OLDH were verified by X-ray diffraction (XRD) and scanning electron microscopy (SEM). A series of poly(propylene carbonate) (PPC)/OLDH composite films with different contents of OLDH were prepared via a melt-blending method. Their cross section morphologies, gas barrier properties and tensile strength were investigated as a function of OLDH contents. SEM results show that OLDH platelets are well dispersed within the composites and oriented parallel to the composite sheet plane. The gas barrier properties and tensile strength are obviously enhanced upon the incorporation of OLDH. Particularly, PPC/2%OLDH film exhibits the best barrier properties among all the composite films. Compared with pure PPC, the oxygen permeability coefficient (OP) and water vapor permeability coefficient (WVP) is reduced by 54% and 17% respectively with 2% OLDH addition. Furthermore, the tensile strength of PPC/2%OLDH is 83% higher than that of pure PPC with only small lose of elongation at break. Therefore, PPC/OLDH composite films show great potential application in packaging materials due to its biodegradable properties, superior oxygen and moisture barrier characteristics.

Thermal, rheological and mechanical properties of poly(propylene carbonate)/methyl methacrylate–butadiene–styrene blends

Different amounts of core–shell methyl methacrylate–butadiene–styrene (MBS) impact modifiers were incorporated into biodegradable poly(propylene carbonate) (PPC) in a batch mixer, aiming at improving the mechanical properties and raising the glass transition temperature (T g) of PPC. A series of properties, such as thermal behavior, miscibility, rheological and mechanical properties, and the morphological analysis of PPC/MBS blends were investigated in detail. PPC was partially miscible with MBS according to the results of dynamic mechanical analysis tests which showed a little shift in the peaks associated with the glass transition temperatures. The differential scanning calorimetry results showed that the T g of PPC increased gradually as MBS content increased. Additionally, the thermal stability properties of the blends were improved dramatically. The rheological properties obtained by the melt flow index tests indicated that the melting viscosities of PPC/MBS blends increased with the addition of MBS, and all melting viscosities of the polymer blends were higher than those of pure PPC. The mechanical properties of PPC/MBS blends implied that the elongation at break increased from 5.3 % of pure PPC to 52 % after incorporation of 20 % MBS into the blends. Accordingly, the impact test results indicated that MBS could toughen the PPC matrix effectively, about 3.7 times higher compared to pure PPC. The scanning electron microscopy studies on PPC/MBS blends showed that MBS particles were dispersed well in the PPC matrix when MBS content was below 10 %, whereas the aggregation could be clearly seen when the content of MBS was over 15 %.

Toughening of poly(propylene carbonate) by carbon dioxide copolymer poly(urethane-amine) via hydrogen bonding interaction

A carbon dioxide copolymer poly(urethane-amine) (PUA) was blended with poly(propylene carbonate) (PPC) in order to improve the toughness and flexibility of PPC without sacrificing other mechanical properties. Compared with pure PPC, the PPC/PUA blend with 5 wt% PUA loading showed a 400% increase in elongation at break, whilst the corresponding yielding strength remained as high as 33.5 MPa and Young’s modulus showed slightly decrease. The intermolecular hydrogen bonding interaction in PPC/PUA blends was confirmed by FTIR, 2D IR and XPS spectra analysis, and finely dispersed particulate structure of PUA in PPC was observed in the SEM images, which provided good evidence for the toughening mechanism of PPC.

Mechanical properties, miscibility, thermal stability, and rheology of poly(propylene carbonate) and poly(ethylene-co-vinyl acetate) blends

Biodegradable polymeric blends are expected to be widely used by industry due to their environmental friendliness and comparable mechanical and thermal properties. In this study, blends of poly(propylene carbonate) (PPC) and poly(ethylene-co-vinyl acetate) (EVA) were prepared. Fourier transform infrared (FTIR) analysis revealed that there were some possible specific interactions between PPC and EVA. The differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA) results showed a single temperature peak of T g between that of pure PPC and that of pure EVA, which suggested that PPC and EVA were compatible. Because of the interfacial interaction between PPC and EVA, EVA could greatly improve the tensile strength, the glass transition temperature and the thermal stability of PPC matrix. Rheological investigation demonstrated that there was a significantly dependence of viscosity on composition. When the EVA content increased, the viscosity began to increase. The PPC/EVA blends could be used as a common biodegradable material for a wide application.