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Antimicrobial resistant (AMR) infections are a growing threat to public health and there is a general lack of development in new antibiotics. Here, a dextran-coated stimuli-responsive nanoparticle (NP) that encapsulates the hydrophobic antibiotic, rifampicin, and specifically binds bacteria to overcome AMR infections is reported. The NP shows a strong affinity with a variety of pathogens in vitro and effectively accumulates in the bacterial infected tissues. The NP is activated by either low pH or high reactive oxygen species in the infectious microenvironment, and releases both cationic polymer and rifampicin that display synergistic activity against AMR pathogens. The NP carrier also enables the antibiotic to penetrate both bacterial biofilms and mammalian cells, thus allowing the elimination of biofilm and intracellular infections. The NP formulation demonstrates both safety and efficacy in two animal infection models against either Gram-negative or Gram-positive AMR pathogens., (© 2021 Wiley-VCH GmbH.)

Gene therapy holds great promise for various medical and biomedical applications. Nonviral gene delivery systems formed by cationic polymer and nucleic acids (e.g., polyplexes) have been extensively investigated for targeted gene therapy; however, their in vitro and in vivo stability is affected by both their intrinsic properties such as chemical compositions (e.g., polymer molecular weight and structure, and N/P ratio) and a number of environmental factors (e.g., shear stress during circulation in the bloodstream, interaction with the serum proteins, and physiological ionic strength). In this review, we surveyed the effects of a number of important intrinsic and environmental factors on the stability of polymeric gene delivery systems, and discussed various strategies to enhance the stability of polymeric gene delivery systems, thereby enabling efficient gene delivery into target cells. Future opportunities and challenges of polymeric nucleic acid delivery nanosystems were also briefly discussed.

Polymeric unimolecular nanoparticles (NPs) exhibiting a core-shell structure and formed by a single multi-arm molecule containing only covalent bonds have attracted increasing attention for numerous biomedical applications. This unique single-molecular architecture provides the unimolecular NP with superior stability both in vitro and in vivo, a high drug loading capacity, as well as versatile surface chemistry, thereby making it a desirable nanoplatform for therapeutic and diagnostic applications. In this review, we surveyed the architecture of various types of polymeric unimolecular NPs, including water-dispersible unimolecular micelles and water-soluble unimolecular NPs used for the delivery of hydrophobic and hydrophilic agents, respectively, as well as their diverse biomedical applications. Future opportunities and challenges of unimolecular NPs were also briefly discussed., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Doping polymer with AlOx via sequential infiltration synthesis enables bulk modification of triboelectric polymers with tunable electric or dielectric properties, which broadens the material selection and achieves a durable performance gain of triboelectric nanogenerators., (© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Brush-shaped amphiphilic block copolymers were conjugated with a monoclonal antibody against CD105 (i.e., TRC105) and a macrocyclic chelator for (64)Cu-labeling to generate multifunctional theranostic unimolecular micelles. The backbone of the brush-shaped amphiphilic block copolymer was poly(2-hydroxyethyl methacrylate) (PHEMA) and the side chains were poly(L-lactide)-poly(ethylene glycol) (PLLA-PEG). The doxorubicin (DOX)-loaded unimolecular micelles showed a pH-dependent drug release profile and a uniform size distribution. A significantly higher cellular uptake of TRC105-conjugated micelles was observed in CD105-positive human umbilical vein endothelial cells (HUVEC) than nontargeted micelles due to CD105-mediated endocytosis. In contrast, similar and extremely low cellular uptake of both targeted and nontargeted micelles was observed in MCF-7 human breast cancer cells (CD105-negative). The difference between the in vivo tumor accumulation of (64)Cu-labeled TRC105-conjugated micelles and that of nontargeted micelles was studied in 4T1 murine breast tumor-bearing mice, by serial positron emission tomography (PET) imaging and validated by biodistribution studies. These multifunctional unimolecular micelles offer pH-responsive drug release, noninvasive PET imaging capability, together with both passive and active tumor-targeting abilities, thus making them a desirable nanoplatform for cancer theranostics.

Stable and tumor-targeting multifunctional wormlike polymer vesicles simultaneously loaded with superparamagnetic iron oxide (SPIO) nanoparticles (NPs) as magnetic resonance imaging (MRI) contrast agent and anticancer drug doxorubicin (DOX) were developed for targeted cancer therapy and ultrasensitive MR imaging. These multifunctional wormlike polymer vesicles were formed by heterobifunctional amphiphilic triblock copolymers R (R = methoxy or folate (FA))-PEG(114)-PLA(x)-PEG(46)-acrylate using a double emulsion method. The long PEG segments bearing methoxy/folate groups (CH(3)O/FA-PEG(114)) were mostly segregated to the outer hydrophilic PEG layers of the wormlike vesicles thereby providing active tumor-targeting ability, while the short PEG segments bearing acrylate groups (PEG(46)-acrylate) were mostly segregated onto the inner hydrophilic PEG layers of the wormlike vesicles thereby allowing the inner PEG layers to be crosslinked via free radical polymerization for enhanced in vivo stability. The hydrophobic anticancer drug, DOX, was loaded into the hydrophobic membrane of the wormlike vesicles. Meanwhile, a cluster of hydrophilic SPIO NPs was encapsulated into the aqueous cores of the stable wormlike vesicles with crosslinked inner PEG layers for ultrasensitive MRI detection. Cellular uptake of the FA-conjugated wormlike vesicles facilitated by the folate receptor-mediated endocytosis process was higher than that of the FA-free vesicles thereby leading to high cytotoxicity against the HeLa human cervical tumor cell line. Moreover, the SPIO/DOX-loaded wormlike vesicles with crosslinked inner PEG layers demonstrated a much higher r(2) relaxivity value than Feridex, a commercially available T(2) agent, which can be attributed to the high SPIO NPs loading level as well as the SPIO clustering effect. These unique stable and tumor-targeting multifunctional SPIO/DOX-loaded wormlike polymer vesicles would make targeted cancer theranostics possible thereby paving the road for personalized medicine., (Copyright © 2010 Elsevier Ltd. All rights reserved.)

A multifunctional stable and pH-responsive polymer vesicle nanocarrier system was developed for combined tumor-targeted delivery of an anticancer drug and superparamagnetic iron oxide (SPIO) nanoparticles (NPs). These multifunctional polymer vesicles were formed by heterofunctional amphiphilic triblock copolymers, that is, R (folate (FA) or methoxy)-poly(ethylene glycol)(M(w):5000)-poly(glutamate hydrozone doxorubicin)-poly(ethylene glycol) (M(w):2000)-acrylate (i.e., R (FA or methoxy)-PEG(114)-P(Glu-Hyd-DOX)-PEG(46)-acrylate). The amphiphilic triblock copolymers can self-assemble into stable vesicles in aqueous solution. It was found that the long PEG segments were mostly segregated into the outer hydrophilic PEG layers of the vesicles, thereby providing active tumor targeting via FA, while the short PEG segments were mostly segregated into the inner hydrophilic PEG layer of the vesicles, thereby making it possible to cross-link the inner PEG layer via the acrylate groups for enhanced in vivo stability. The therapeutic drug, DOX, was conjugated onto the polyglutamate segment, which formed the hydrophobic membrane of the vesicles using a pH-sensitive hydrazone bond to achieve pH-responsive drug release, while the hydrophilic SPIO NPs were encapsulated into the aqueous core of the stable vesicles, allowing for ultrasensitive magnetic resonance imaging (MRI) detection. The SPIO/DOX-loaded vesicles demonstrated a much higher r(2) relaxivity value than Feridex, a commercially available SPIO-based T(2) contrast agent, which was attributed to the high SPIO NPs loading level and the SPIO clustering effect in the aqueous core of the vesicles. Results from flow cytometry and confocal laser scanning microscopy (CLSM) analysis showed that FA-conjugated vesicles exhibited higher cellular uptake than FA-free vesicles which also led to higher cytotoxicity. Thus, these tumor-targeting multifunctional SPIO/DOX-loaded vesicles will provide excellent in vivo stability, pH-controlled drug release, as well as enhanced MRI contrast, thereby making targeted cancer therapy and diagnosis possible.

A new type of multifunctional unimolecular micelle drug nanocarrier based on amphiphilic hyperbranched block copolymer for targeted cancer therapy was developed. The core of the unimolecular micelle was a hyperbranched aliphatic polyester, Boltorn H40. The inner hydrophobic layer was composed of random copolymer of poly(ε-caprolactone) and poly(malic acid) (PMA-co-PCL) segments, while the outer hydrophilic shell was composed of poly(ethylene glycol) (PEG) segments. Active tumor-targeting ligands, i.e., folate (FA), were selectively conjugated to the distal ends of the PEG segments. An anticancer drug, i.e., doxorubicin (DOX) molecules, was conjugated onto the PMA segments with pH-sensitive drug binding linkers for pH-triggered drug release. Transmission electron microscopy (TEM) and dynamic light scattering (DLS) analysis showed that the unimolecular micelles were uniform with a mean hydrodynamic diameter around 25 nm. The drug loading content was determined to be 14.2%. The drug release profile, cell uptake and distribution, and cytotoxicity of the unimolecular micelles were evaluated in vitro. The folate-conjugated micelles can be internalized by the cancer cells via folate-receptor-mediated endocytosis; thus, they exhibited enhanced cell uptake and cytotoxicity. At pH 7.4, the physiological condition of bloodstream, DOX conjugated onto the unimolecular micelles exhibited excellent stability; however, once the micelles were internalized by the cancer cells, the pH-sensitive hydrazone linkages were cleavable by the intracellular acidic environment, which initially caused a rapid release of DOX. These findings indicate that these unique unimolecular micelles may offer a very promising approach for targeted cancer therapy.

Thermosensitive PNVCL-b-PEG block copolymer coupled with folic acid was prepared as an anti-cancer drug carrier. This polymer self-assembled into stable micelles in aqueous solutions at above 33 degrees C. At 37 degrees C, the release profile of PNVCL-b-PEG-FA micelles showed a slower and more controlled release of the entrapped 5-FU than that at 25 degrees C. The blank and 5-FU-loaded PNVCL-b-PEG-FA micelles did not induce remarkable cytotoxicity against the EA.hy 926 human endothelial cell line; however, 5-FU-loaded PNVCL-b-PEG-FA micelles showed a cytotoxicity effect against 4T1 mouse mammary carcinoma cells due to the availability of loaded anti-cancer drugs delivered to the inside of the cancer cells by the folate-receptor-mediated endocytosis process.

Folate-conjugated amphiphilic hyperbranched block copolymer (H40-PLA-b-MPEG/PEG-FA) with a dendritic Boltorn H40 core, a hydrophobic poly(l-lactide) (PLA) inner shell and a hydrophilic methoxy poly(ethylene glycol) (MPEG) and folate-conjugated poly(ethylene glycol) (PEG-FA) outer shell was synthesized as a carrier for tumor-targeted drug delivery. The block copolymer was characterized using (1)H NMR and gel permeation chromatography (GPC) analysis. Due to its core-shell structure, this block polymer forms unimolecular micelles in aqueous solutions. The micellar properties of H40-PLA-b-MPEG/PEG-FA block copolymer were extensively studied by dynamic light scattering (DLS), fluorescence spectroscopy, and transmission electron microscopy (TEM). An anticancer drug, doxorubicin in the free base form (DOX) was encapsulated into H40-PLA-b-MPEG/PEG-FA micelles. The DOX-loaded micelles provided an initial burst release (up to 4h) followed by a sustained release of the entrapped DOX over a period of about 40 h. Cellular uptake of the DOX-loaded H40-PLA-b-MPEG/PEG-FA micelles was found to be higher than that of the DOX-loaded H40-PLA-b-MPEG micelles because of the folate-receptor-mediated endocytosis, thereby providing higher cytotoxicity against the 4T1 mouse mammary carcinoma cell line. In vitro degradation studies revealed that the H40-PLA-b-MPEG/PEG-FA block copolymer hydrolytically degraded into polymer fragments within six weeks. These results indicated that the micelles prepared from the H40-PLA-b-MPEG/PEG-FA block copolymer have great potential as tumor-targeted drug delivery nanocarriers.

A novel type of biodegradable/biocompatible amphiphilic hyperbranched copolymer (H40-PLA-b-MPEG) was synthesized. Its micellar properties were studied by DLS, fluorescence spectroscopy and TEM. The drug release profile showed that the H40-PLA-b-MPEG micelles provide an initial burst release, followed by a sustained release of the entrapped hydrophobic model drug over a period of 4 to 58 h. The copolymer degraded hydrolytically within 6 weeks under physiological conditions. The MTT assay showed no obvious cytotoxicity against a human endothelial cell line at a concentration range of 0-400 microg x mL(-1). These results indicate that the H40-PLA-b-MPEG micelles have great potential as hydrophobic drug delivery carriers.

Multi-arm star amphiphilic block copolymers (SABCs) with approximately 32 arms were synthesized and characterized for drug delivery applications. A hyperbranched polyester, boltorn H40 (H40), was used as the macroinitiator for the ring-opening polymerization of epsilon-caprolactone (epsilon-CL). The resulting multi-arm H40-poly(epsilon-caprolactone) (H40-PCL-OH) was further reacted with carboxyl terminated methoxy poly(ethylene glycol) (MPEG-COOH) to form H40-PCL-b-MPEG copolymers. The resulting SABCs were characterized by (1)H NMR spectroscopy and gel permeation chromatography (GPC). The critical aggregation concentration (CAC) of H40-PCL-b-MPEG was 3.8 mg/L as determined by fluorescence spectrophotometry. Below the CAC, stable unimolecular micelles were formed with an average diameter of 18 nm as measured by TEM. Above the CAC, unimolecular micelles exhibited agglomeration with an average diameter of 98 nm. The hydrodynamic diameter of these agglomerates was found to be 122 nm, as measured by dynamic light scattering (DLS). The drug loading efficacy of the H40-PCL-b-MPEG micelles was 26 wt%. Drug release study showed an initial burst followed by a sustained release of the entrapped hydrophobic model drug, 5-fluorouracil, over a period of 9-140 h. These results indicate that the H40-PCL-b-MPEG micelles have great potential as hydrophobic drug delivery carriers.

A novel type of pH- and thermo-responsive copolymer, chitosan-graft-poly(N-vinylcaprolactam) (chitosan-g-PNVCL), was prepared by grafting carboxyl-terminated poly(N-vinylcaprolactam) (PNVCL-COOH) chains onto a chitosan backbone as a drug-delivery carrier. The formation of chitosan-g-PNVCL was confirmed by FT-IR and 1H NMR techniques. Chitosan-g-PNVCL showed a definite phase transition at 32 degrees C as occurs in pure PNVCL. The swelling degree of the chitosan-g-PNVCL beads was found to be higher at pH 2.2 than at pH 7.4. Moreover, the swelling degree of the beads decreased with increased environmental temperature. Compared to the chitosan beads, the release profile of chitosan-g-PNVCL beads showed a slower and more controlled release of the entrapped ketoprofen. The release behavior of the chitosan-g-PNVCL beads was influenced by both the pH and temperature of the medium. The MTT assay showed no obvious cytotoxicity of chitosan-g-PNVCL against a human endothelial cell line over a concentration range of 0-400 microg x mL(-1). These results suggest that chitosan-g-PNVCL could be a potential stimuli-responsive material for controlled drug delivery, and it may improve the bioavailability, efficacy, and compliance of the encapsulated drugs. [Reaction: see text].

Versatile wood cellulose, the most prototypical abundant polymer on earth, is considered a promising natural material for the fabrication of biodegradable electronics. The development of biodegradable electronics may help alleviate the adverse environmental impact caused by the fast‐growing electronic waste (e‐waste). The focus of this review is to discuss recent major advances in biodegradable electronics with versatile wood cellulose in terms of supporting substrates and functional components. First, the biological biodegradation and structural hierarchy of versatile wood cellulose is briefly introduced, followed by highlighting three types of cellulose substrates (opaque and hazy cellulose paper, transparent and clear cellulose film, and transparent and hazy cellulose film) for biodegradable electronics. Then, recent progress and research achievements in the use of versatile wood cellulose with multiscale dimensions in biodegradable electronics as a functional component (e.g., advanced light management layer, high capacitance dielectric, and ionic conductor) or even smart materials (e.g., mechanochromic layer, humidity sensing layer, adaptable adhesive layer, and piezoelectric component) are summarized in detail. Finally, an overview of challenges and perspectives for biodegradable electronics with versatile cellulose is provided. [ABSTRACT FROM AUTHOR]

Abstract: A novel class of high performance polymer porous aerogel film‐based triboelectric nanogenerators (A‐NGs) is demonstrated. The A‐NGs, made of a pair of highly porous polymer films, exhibit much higher triboelectric outputs than the corresponding dense polymer film‐based triboelectric nanogenerators (D‐NGs) under the same mechanical stress. The triboelectric outputs of the A‐NGs increase significantly with increasing porosity, which can be attributed to the increase in contact area and the electrostatic induction in the porous structure, thereby leading to additional charges on the porous surface. Remarkably, the A‐NG fabricated using porous chitosan aerogel film paired with the most porous polyimide (with a porosity of 92%) aerogel film demonstrates a very high voltage of 60.6 V and current of 7.7 µA, corresponding to a power density of 2.33 W m−2, which is sufficient to power 22 blue light‐emitting‐diodes (LEDs). This is the first report on triboelectric nanogenerators (TENGs) employing porous polymer aerogel films as both positive and negative materials to enhance triboelectric outputs. Furthermore, enhancing the tribopositive polarity of the cellulose aerogel film via silanization using aminosilane can dramatically improve the triboelectric performance. Therefore, this study provides new insights into investigating porous materials with tunable triboelectric polarities for high performance TENGs. [ABSTRACT FROM AUTHOR]

Supercritical fluid (SCF) N2 was used as a physical foaming agent to fabricate microcellular injection-molded poly(hydroxybutyrate-co-hydroxyvalerate) (PHBV)–poly(butylene adipate-co-terephthalate) (PBAT)–hyperbranched-polymer (HBP)–nanoclay (NC) bionanocomposites. The effects of incorporating HBP and NC on the morphological, mechanical, and thermal properties of both solid and microcellular PHBV–PBAT blends were studied. NC exhibited intercalated structures in solid components, but showed a mixture of exfoliated and intercalated structures in the corresponding microcellular nanocomposites. The addition of NC improved the thermal stability of the resulting nanocomposites. The addition of HBP and NC reduced the cell size and increased the cell density of microcellular components. The addition of HBP and NC enhanced the degree of crystallinity for both solid and microcellular components. Moreover, with the addition of HBP, the area under tan δ curve, specific fracture toughness, and strain-at-break of the PHBV-based nanocomposite increased significantly whereas the storage modulus, specific Young’s modulus, and specific tensile strength decreased. [ABSTRACT FROM PUBLISHER]

The effects of incorporating hyperbranched polymers (HBPs) and different nanoclays [Cloisite® 30B and halloysite nanotubes (HNT)] on the mechanical, morphological, and thermal properties of solid and microcellular poly(hydroxybutyrate- co-hydroxyvalerate) (PHBV) were investigated. According to the X-ray diffraction (XRD) and transmission electron microscopy (TEM) analyses, Cloisite 30B exhibited a combination of exfoliation and heterogeneous intercalation structure for both solid and microcellular PHBV-12% HBP-2% Cloisite 30B nanocomposites. TEM images indicated that HNTs were uniformly dispersed throughout the PHBV matrix. The addition of 2% nanoclays improved the thermal stability of the resulting nanocomposites. The addition of HBP+poly(maleic anhydride- alt-1-octadecene) (PA), Cloisite 30B, and HNT reduced the average cell size and increased the cell density of the microcellular components. The addition of (HBP+PA), Cloisite 30B, and HNT also increased the degree of crystallinity for both solid and microcellular components in comparison with neat PHBV. Also, with the addition of 12% (HBP+PA), the area under the tan-δ curve, specific toughness, and strain-at-break of the PHBV-HBP nanocomposite increased significantly for both solid and microcellular specimens, whereas the storage modulus, specific Young's modulus, and specific tensile strength decreased. The addition of 2% nanoclays into the PHBV-HBP nanocomposites improved the storage modulus, specific Young's modulus, and specific tensile strength of the PHBV-HBP-nanoclay-based nanocomposites, but they were still lower than those of the neat PHBV. POLYM. ENG. SCI., 2011. © 2011 Society of Plastics Engineers [ABSTRACT FROM AUTHOR]

The article discusses a study that focuses on recycled wood fibers (RWFs) which when blended with biobased and biodegradable composite like polylactide (PLA) forms a fully bio-based and biodegradable composite with enhanced material properties. It cites the importance of using a coupling agent for better adhesion as cellulose-based wood fibers have poor interfacial adhesion. It suggests an increase in the tensile modulus with RWF content as the toughness and strain-at-break decreased.

Abstract: A novel thiolated carboxymethyl chitosan-g-β-cyclodextrin (CMC-g-β-CD) drug delivery carrier was synthesized and characterized. Thiolated CMC-g-β-CD was synthesized using two steps. First, carboxymethyl β-cyclodextrin (CM β-CD) was grafted onto carboxymethyl chitosan (CMC) using water-soluble 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDC) and N-hydroxysuccinimide (NHS) as the condensing agents. Next, the resultant product was further grafted with cysteine methyl ester hydrochloride (CMEH). Its structure was confirmed by FT-IR and 1H NMR spectral analysis. X-ray diffraction (XRD) analysis on the resulting product showed that the peaks at 2θ =10° and 20° decreased greatly in thiolated polymers, indicating that these polymers are more amorphous in nature. The swelling study showed that the water uptake of thiolated CMC-g-β-CD was higher than that of the unmodified chitosan control. The adhesive properties of thiolated CMC-g-β-CD were evaluated in vitro on a freshly excised mouse mucosa, and a fivefold increase in the adhesion time was found in thiolated CMC-g-β-CD when compared with the unmodified chitosan control. The drug release profile showed that thiolated CMC-g-β-CD tablets provided a slower release of the entrapped hydrophobic model drug, ketoprofen, than the chitosan control, and the release behavior was influenced by the amounts of thiol groups present on the polymer chains. These results suggest that thiolated CMC-g-β-CD with improved mucoadhesive properties may potentially become an effective hydrophobic drug delivery system with controlled drug release capability. [Copyright &y& Elsevier]

Explores the processing benefits and property improvements of combining nanocomposites with microcellular injection molding. Performance of the microcellular nanocomposite processing on an injection-molding machine equipped with a commercially available supercritical fluid system; Analysis of pertinent topics and relevant issues; Implications on polymer engineering and science.

Abstract: Poly(trimethylene carbonate)-block-poly(ethylene glycol)-block-poly(trimethylene carbonate) (PTMC–PEG–PTMC) triblock copolymers were synthesized successfully by the microwave-assisted ring-opening copolymerization of trimethylene carbonate (TMC) and poly(ethylene glycol) (PEG). The polymerizations were carried out in a single-mode microwave oven in the absence of any metallic compound catalyst. In the presence of PEG600, PTMC–PEG–PTMC triblock copolymer with a number-average molar mass of 16,600g/mol and a TMC conversion of 97% could be synthesized after the TMC/PEG600 reaction mixture was irradiated at 120°C for 60min. Both the molar mass of the resulting triblock copolymer and TMC conversion produced by the microwave method were higher than those produced by the conventional method. Thermal properties of the resulting polymers were studied by differential scanning calorimetry. [Copyright &y& Elsevier]

Abstract: Poly(trimethylene carbonate) (PTMC) was synthesized successfully by microwave-assisted ring-opening polymerization of trimethylene carbonate. The polymerizations were carried out in a single-mode microwave oven using ethylene glycol (EG) as the initiator in the absence of any metallic compound catalyst. The temperature–time profiles of the reaction mixture were investigated at different power levels and EG concentrations. The molar mass of the resulting PTMC and TMC monomer conversion by the microwave method is higher than those by the conventional method. Thermal properties of the resulting polymers were studied by differential scanning calorimetry. Microwave irradiation proved to be an effective and efficient method for the preparation of PTMC. [Copyright &y& Elsevier]

Abstract: Foamed poly(lactide) (PLA)/poly(butylene adipate-co-terephthalate) (PBAT) blends were processed via the microcellular extrusion process using CO2 as a blowing agent. Talc has been added to promote heterogeneous nucleation. Two types of PLA/PBAT blend systems were investigated: Ecovio, which is a commercially available compatibilized PLA/PBAT blend; and a non-compatibilized PLA/PBAT blend at the same PLA/PBAT ratio (i.e., 45:55 by weight percent). Six different formulations were investigated: pure PLA, PLA-talc, Ecovio, Ecovio-talc, non-compatibilized PLA/PBAT blend, and non-compatibilized PLA/PBAT-talc. The effects of various processing parameters such as die temperature, talc and compatibilization on various foaming properties such as cell morphology, volume expansion ratio (VER), open cell content (OCC) and crystallinity were investigated. As per the DSC thermograms, it was observed that compatibilization has merged the two distinctive melting peaks of PLA and PBAT into a single peak while lowering the peak temperature. In general, the addition of talc has decreased the average cell size and VER and increased the cell density and crystallinity; however, it has varying effects on the open cell content. Compatibilization has reduced the average cell size and volume expansion but increased the cell density and had varying and no effects on the OCC and crystallinity, respectively. Similar to compatibilization, the die temperature was found to have varying and no effects on the OCC and crystallinity, respectively. Except for PLA and non-compatibilized PLA/PBAT blend, the cell size and VER of all other formulations did not vary much throughout the entire temperature range (130–150°C). The cell density was found to be insensitive to die temperatures except for Ecovio and Ecovio-talc. [Copyright &y& Elsevier]

Abstract: This paper presents a thin polymer surface coating approach to facilitate dispersion of poly(styrene-maleic anhydride) (SMA) copolymer-coated alumina (Al2O3) nanoparticles in polycarbonate (PC) using a high intensity thermokinetic mixer (K-mixer) and the optical properties of the resultant nanocomposites. Electron spectroscopy for chemical analyses (ESCA), energy filtered transmission electron microscopy (EFTEM), thermogravimetric analysis (TGA), and field emission scanning electron microscopy (FESEM) were used to investigate the covalent bonding of polymer coating on the nanoparticles and the nanoparticle dispersion. The light transmittance of the PC/alumina nanocomposites was measured and compared with that of the transparent neat resin. [Copyright &y& Elsevier]