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In this paper, a natural polymer, zein, is converted into a disposable and environmentally friendly surface enhanced Raman spectroscopy (SERS) biosensor platform to detect toxins. First, protein nanofiber mats were fabricated using electrospinning. Next, the surface of the fibers was decorated with metallic nanoparticles to create hotspots for the detection of the target molecule. Four types of metallic nanoparticles were tested for sensitivity optimization: gold, silver, silver‐shelled‐gold, and a mixture of gold and silver nanoparticles. Silver‐shelled‐gold nanoparticles gave the highest SERS intensity, and at the concentration of 1012 particles/ml, the highest enhancement factor (EF) of 2.49 × 106 was reached, which is the highest EF ever reported for a zein‐based biodegradable platform. Acrylamide was used as the model food carcinogenic toxin and its detection with this nanofiber‐based platform gave a limit of detection of 2.06 ng/ml. This LOD is 104 times lower than the limit of detection that was achieved previously with a zein‐based SERS platform. Other sensitive analytical methods (GC–MS and LC–MS/MS) gave LODs of 5–10 and 20–50 ng/ml for acrylamide, much higher than the method used in this study. This sensitivity is much lower than any other previous attempts to detect acrylamide with biodegradable sensors. [ABSTRACT FROM AUTHOR]

The theoretical prediction of the mechanical behavior of fibrous materials for medicine in different environments is of great scientific interest. The deformation mechanisms under loading of biopolymer electrospun fibrous materials differ significantly in dependence on the phase state of the medium, namely, liquid state, gaseous state, or at their interface. In this paper, the influence of various mediums on the mechanical behavior of fibrous materials based on poly‐3‐hydroxybutyrate under tension is examined. The oxidative stress (ozone treatment) and the incorporation of low concentrations of modifying additives (complexes of tetraphenyl‐porphyrin with Zn) are proposed as the most effective methods of directed control of stress‐related characteristics without a negative effect on the functional properties of medical materials. [ABSTRACT FROM AUTHOR]

Lignin is a natural polymer produced in huge amounts by the paper industry. Innovative applications of lignin, especially in agriculture, represent a valuable way to develop a more sustainable economy. Its antioxidant and antimicrobial properties, combined with its biodegradability, make it particularly attractive for the development of plant protection products. Copper is an element that has long been used as a pesticide in agriculture. Despite its recognized antimicrobial activity, the concerns derived from its negative environmental impact is forcing research to move toward the development of more effective and sustainable copper‐based pesticides. Here a simple and sustainable way of synthesizing a new hybrid material composed of Cu2O nanocrystals embedded into lignin, named Lignin@Cu2O is presented. The formation of cuprite nanocrystals leaves the biopolymer intact, as evidenced by infrared spectroscopy, gel permeation chromatography, and Pyrolysis‐GC analysis. The combined activity of lignin and cuprite make Lignin@Cu2O effective against Listeria monocytogenes and Rhizoctonia solani at low copper dosage, as evidenced by in vitro and in vivo tests conducted on tomato plants. [ABSTRACT FROM AUTHOR]

Lignin, as the second most abundant natural polymer, has not been fully utilized in the industrial field due to the complex structure and functional groups. In this paper, polyvinyl chloride (PVC) coated lignin‐silica composites (PLS) with excellent cycling performance are prepared from rice husk and PVC through the method of alkali extraction and acid precipitation and mechanical mixing process. Due to the existence of functional groups on the surface of lignin, it can be closely combined with PVC to form a stable structure. The first discharge specific capacity and Coulombic efficiency of PLS is 1436 mA h g−1 and 56 %, respectively, and the reversible capacity is 720 mA h g−1 after 200 cycles at 0.1 A g−1, showing a stable cycling performance. This work promotes the application of lignin in the SiO2/C anode material of lithium ion battery, and confirms the stable combination between PVC and organic carbon. [ABSTRACT FROM AUTHOR]

A surgical procedure for the repair of damaged periodontal tissue is Guided Tissue Regeneration (GTR), which involves the use of a barrier membrane to prevent soft tissue ingrowth and create a space for slow regeneration of periodontium and bone. GTR membrane should have pores able to facilitate the diffusion of fluids, oxygen, nutrients, and bioactive substances for cell growth, but also be impermeable to epithelial cells or gingival fibroblasts, which could overpopulate the defect space and inhibit infiltration and activity of bone‐forming cells. In this paper, a bilayer PLGA membrane was realized by coupling the dip coating and electrospinning techniques. The rough layer of the double‐sided structure was electrospun on the previously prepared smooth dip‐coated membrane. A rotating drum collector at two rotating speeds was used to generate different fibers orientation. The bilayer membrane with different superimposed surfaces was successfully fabricated and characterized from a morphological, physicochemical, and the mechanical point of view. Performed analyses revealed that the membrane possesses suitable properties, especially from mechanical point of view, for its possible use as a scaffold for the GTR of periodontum. A high fiber alignment and improved mechanical properties with respect to available GTR membranes characterized the product resulting from this study. [ABSTRACT FROM AUTHOR]

The runnability and convertibility of biopolymer dispersion-coated paperboard were determined using a novel adjustable packaging line equipped with a tray-pressing mould. Commercial paperboard was dispersion barrier coated on the back-side using a dual polymer system containing both a synthetic and a renewable biopolymer, of which the latter was the main component in the dispersion. The effect of the addition of a high-aspect-ratio platy pigment and synthetic polymer on both the grease resistance and the convertibility of the product was evaluated in addition to the evaluation of runnability and crack resistance in tray pressing and die cutting. The addition of synthetic polymer into bio-based dispersion improved the elastic properties, plasticity and, subsequently, mechanical convertibility of the product. Moderate additions of the synthetic polymer provided improved grease resistance for the biopolymer coatings. It revealed that the addition of synthetic polymer was sufficient in providing improved barrier properties, although the chemical compatibility and process window for the convertibility need to be considered. In addition to mechanical stability, the heat stability of the substrate needs to be investigated. Copyright © 2013 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Inverse vulcanization of cheap elemental sulfur (S) to prepare polymers that simultaneously possess high sulfur content and good solubility is still in its infancy. In this paper, the authors report the synthesis of a novel S‐rosin (Ro) copolymer (Sx‐Ro) based on the inverse vulcanization of S with natural Ro. The sulfur content of Sx‐Ro can be regulated in a wide range, while Sx‐Ro still presents excellent solubility in low boiling point solvents at high sulfur content. Even if the sulfur content in Sx‐Ro is as high as 50%, its solubility in tetrahydrofuran (THF) can still reach 26 mg mL−1. Moreover, the Sx‐Ro exhibits excellent ultraviolet (UV) absorption capability in the entire UV region (200–400 nm) and can be utilized as an effective anti‐UV agent to enhance the UV‐blocking performance of other polymers (e.g., polymethyl methacrylate [PMMA] and polystyrene [PS]) without compromise of transparency and thermal stability. Considering the fine solubility and superior UV‐blocking properties of Sx‐Ro, this work not only provides a versatile and effective anti‐UV material but also opens new opportunities for value‐added utilization of abundant S and Ro resources. [ABSTRACT FROM AUTHOR]

Self‐healing polymer materials have been developed rapidly over the past 20 years, which can replace thermosetting materials to a certain extent, repair damage without manual intervention, prolong service life, and compress usage cost. The self‐healing polymer materials derived from biomass resources can reduce the dependence on traditional non‐renewable resources such as petroleum. The structures and properties of biomass based self‐healing polymer materials are of great significance for their processing, recycling and self‐healing. In this paper, the research progress of bio‐based self‐healing polymer materials based on dynamic non‐covalent bonds and dynamic covalent bonds including hydroxyl ester, Schiff base, disulfide bond, and hydroxyl urethane derived from vegetable oil, lignin, cellulose, vanillin and natural rubber were reviewed, and the dynamic non‐covalent bonds and dynamic covalent bonds were also introduced. The applications of various dynamic covalent bonds and dynamic non‐covalent bonds in the design and construction of polymer materials were reviewed, and the future development of dynamic covalent polymer materials was prospected. [ABSTRACT FROM AUTHOR]

This scientific paper emphasizes the synthesis of a bio‐based tannic acid epoxy (TAE100) with high bio‐content obtained by simple surface modification of tannic acid (TA). The resin was further cured with a biobased hardener poly(amido amine). Three contrast epoxy resins were also prepared with 50%, 75%, and 90% TA along with the rest amount of bisphenol A (BPA). Upon investigating mechanical properties, TAE100 exhibited a maximum tensile strength of 18.4 MPa (against 3.1–15.3 MPa for partially bio‐based ones) with 16% of elongation at break (against 39.1%–63.5% for partially bio‐based ones). The high adhesive strength (4545 MPa) obtained for TAE100 (compared to 881–2715 MPa for partially biobased ones) on wood‐wood surfaces reflecting good adhesive character of the bio‐based epoxy and offered potential applicability in the field of eco‐coatings and adhesives. Two‐stage thermal degradation behavior with initial decomposition temperature of 232°C revealed its good thermostability. Most importantly, the thermosets were biodegradable, as indicated by the microbial test. [ABSTRACT FROM AUTHOR]

The demand for energy‐efficient water treatment as well as the limitation in adsorption of existing membranes has motivated the pursuit of membranes that can break the selectivity‐permeability trade‐off and provide high selective adsorption for chemicals of interest. The membrane adsorbers have received a lot of attention for removing contaminants from aqueous solution due to combine both advantages of adsorption and membrane separation. Membrane adsorbers constructed by biopolymer with many functional groups are widely used in water purification, because the biopolymers are easily available from biomass materials in nature, degradable, and low‐cost. This paper summarizes the characteristics and important development direction of these types of biomass‐based membrane adsorption materials to adsorb organic/inorganic contaminants of water and analyzes the preparation methods of natural biomacromolecule cellulose, chitosan, sodium alginate, and protein to construct the membrane adsorption materials, as well as the application of pollutant removal from aqueous solutions. According to the current problems and shortcomings in the research of biopolymer‐based membrane adsorbers, it is proposed to improve the understanding of the adsorption mechanism of biopolymer‐based membrane adsorbers and accelerate the development of practical applications as the focus of future research. [ABSTRACT FROM AUTHOR]

Plastic films used to make market bags are based on polymers such as polyethylene, polystyrene and polypropylene. These materials require a long time to degrade in the environment. Alternative technologies have been developed to reduce the degradation time and the impact on the environment caused by the conventional polymer materials, using pro-degrading additives or by the development of biodegradable polymers. In Brazil, some city's laws require the use of biodegradable material in the production of market bags, but the absence of specific surveillance policies makes their chemical composition unknown. The plastic bags didn't show the expected environmental behavior by the manufactures, so it is important to understand the reasons why they are not biodegradable in Brazilian landfills. In this paper, 7 samples that were obtained from a trading company and commercial market of Belo Horizonte were analyzed. The samples were characterized by biodegradable analysis, XRF, FTIR, SEM and TGA/DTA, which allowed the identification and evaluation of the thermal behavior of the material in an inert and oxidizing atmosphere. The results showed that plastic bags were composed by a mixture of PLA and PBAT, with possible presence of TPS and titanium and calcium fillers. All samples presented low biodegradability in compostable environment. [ABSTRACT FROM AUTHOR]

The utilization of lipids is presently in the spotlight of food industry as they are one of novel renewable and sustainable raw materials. Lipids derived materials are considered as a promising alternate to petro‐based polymers as they are sustainable, biorenewable, biodegradable, and environmentally benign. These unique attributes draw the attention of scientific community for the use of lipids in food packaging applications with a potential to compete with fossil fuel derived polymers. This paper reviews recent advances in the use of lipids and their effect on the barrier, antimicrobial, antioxidant, and mechanical properties of films, coating and nanocomposites for food packaging applications. Modification of lipids and its chemical interactions with other biopolymers during processing for the synthesis of different materials are also discussed. Global patents and research trend in use of lipids for the preparation of biocomposites are also described. The role of lipids in the circular economy is highlighted and life cycle assessment of lipids derived products is outlined with examples. The review is concluded with synoptic view of existing and forthcoming potential use of lipids in various food packaging applications. [ABSTRACT FROM AUTHOR]

1. Experiments with enzyme preparations produced from Chaetomium globosum grown on various polysaccharides showed that xylanase is an adaptive specific enzyme, which is only produced in the presence of xylan in the medium. 2. Paper-chromatographic tests proved that the principal products of hydrolysis are xylose, besides a small amount of arabinose and a water-soluble, enzyme-resistant polysaccharide. This polysaccharide does not move on the paper chromatogram, and yielded on acid hydrolysis xylose, arabinose, and glucose in approximately equal amounts together with a comparatively slight amount of a uronic acid. 3. When proper xylanase preparations are used a series of spots moving slower than the pentoses and the hexoses and with regularly decreasing Rf values appear on the chromatogram. These spots are interpreted to represent molecular fragments with increasing number of xylose units, resulting from random scission of the glycosidic linkages of the polyxyloside chain. The fastest moving of these compounds may consist of two xylose units and be an analogue of cellobiose. 4. Heating or storing of xylanase preparations resulted in almost complete removal of the power to produce xylose, whereas slower moving spots representing intermediate products of hydrolysis still appeared on the chromatogram, suggesting that two components are present in the xylanase. [ABSTRACT FROM AUTHOR]

Lignin is one of the primary components of lignocellulosic biomass. It is an alternative and sustainable source for aromatic and cyclic hydrocarbons. Lignin is obtained in large quantities as a co‐product in sugar, paper‐pulp, and bioethanol industries. Hydrodeoxygenation/‐hydrogenation of lignin‐based phenolic compounds is an important route to synthesize new generation products. This review focuses on recent catalytic methods for selective conversion of phenolics into cyclohexa(nol/none/ne); which are precursors for emerging polymers and fuels. Furthermore, effect of metal catalysts, supports, and parameters on different reactions were discussed along with possible industrial applications of obtained cycloalkanes. In addition, limitations, advantages, and future scope of hydrodeoxygenation/‐hydrogenation of monolignols are also described. [ABSTRACT FROM AUTHOR]

Biopolymer films particularly starch films are promising alternatives to non‐biodegradable petroleum‐based materials because they are cheap, available in abundance, and biodegradable. Nonetheless, the weak mechanical and barrier properties of the films restrict their usage. Other additives such as essential oils (EOs) incorporate into the films may enhance the restricted properties and add functionality to films. However, knowledge of the effects of EOs addition in starch films across food packaging applications is not fully elucidated. This paper provides an overview of the various types of EOs used in the production of starch films produced via the solvent casting method, the effects of EOs on the properties of starch films, and the application of the films for food packaging, particularly for fruits and meats. The films bring a high potential to extend the shelf life of food due to the antioxidant and antimicrobial properties of the EOs. [ABSTRACT FROM AUTHOR]

The paper describes the preparation of polymeric hydrogels, loaded with bupivacaine, which could represent a good alternative in clinical dentistry as local anesthetics. The hydrogels were prepared by condensation using an amidation reaction between a natural polymer (chitosan) and a synthetic one, poly[(maleic anhydride)‐alt‐(vinyl acetate)]. Infrared spectroscopy studies confirmed crosslinking through the presence of amide bonds, formed between the two types of polymer chains. Scanning electron microscopy results demonstrated that the hydrogels have a porous structure, the pore dimensions being non‐uniform with diameters between 200 and 600 μm. Hydrogels presented good bupivacaine inclusion and release capacity whereas theoretical analysis confirmed the validity of the generalized fractal model, reinforcing a csavi‐universal pattern of drug release. Cytotoxicity tests on human dermal fibroblasts revealed that the obtained hydrogels are not cytotoxic. In vivo, the bupivacaine‐loaded hydrogels presented anesthetic effects after 15 min and no side effects were observed. This system has the advantage of alleviating or eliminating pain associated with invasive procedures and avoiding direct contact of the drug with tissues, leading thus to the prevention of side effects. © 2020 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

In this paper, horseshoe crab exoskeleton and exuviae were collected on the coasts of Yucatan and physicochemical studies were carried out. Samples from different sections of the exoskeleton were taken to evaluate chitin content and properties in order to be compared with exuviae. The isolation of chitin was realized by chemical processes involving deproteinization, demineralization and discoloration. Physicochemical properties of chitin extracted from both sources were compared in terms of characterization analysis in particular achieved under EDX, FTIR and calorimetric techniques (DSC and TGA). In such comparative analysis lies the importance to establish differences or similitudes in chitin contents, structure, etc. Scanning Electron Microcopy was conducted on exuviae and exoskeleton selected parts in order to identify horseshoe crab structure and surface morphology. Differential scanning calorimetry was focused on changes in physical and chemical structures at different samples showing two endothermic peaks related to the complete elimination of hydroxyl groups attached to polysaccharide rings. TGA thermograms were characterized by endo and exotherms corresponding to water evaporation and decomposition of polymer respectively. Exoskeleton SEM images shown a tubular network and porous surface while exuviae exhibited irregular surface and diatom unicellular microalgae embedded. Calorimetric measurements confirmed that exuviae is richer in chitin than exoskeleton and that the main allotropic crystal structure corresponds to α‐chitin. FTIR analysis supported these results by exhibiting different absorption bands corresponding to α‐chitin. [ABSTRACT FROM AUTHOR]

Hydrogels, characterised as highly hydrophilic three‐dimensional polymer networks, have gained increasing attention due to their unique physicochemical properties, finding applications in various fields. Natural polymer hydrogels exhibit higher biocompatibility and biodegradability compared to traditional synthetic polymer hydrogels. Proteins, being the principal materials of natural polymer hydrogels, bear numerous modifiable functional groups. The resultant hydrogel possesses responsiveness, adjustable degradability, and underway as an excellent biomaterial. Seven common raw materials used to construct protein hydrogels are introduced. In terms of comparing natural polymer hydrogels with traditional synthetic polymer hydrogels, the authors conduct a detailed analysis and comparison, highlighting the advantages of natural polymer hydrogels in terms of biocompatibility and biodegradability, and summarising their characteristics. The authors also address the limitations of various protein hydrogels and list existing strengthening cross‐linking strategies, proposing new insights to overcome the application limits of protein hydrogels. Additionally, the applications of protein hydrogels in drug delivery, biosensing, bio‐inks and tissue engineering are discussed. The authors conclude by summarising the current challenges faced by protein hydrogels and prospecting its future development. [ABSTRACT FROM AUTHOR]

The separator is an essential component of sodium‐ion batteries (SIBs) to determine their electrochemical performances. However, the separator with high mechanical strength, good electrolyte wettability and excellent electrochemical performance remains an open challenge. Herein, a new separator consisting of amphoteric nanofibers with abundant functional groups was fabricated through supramolecular assembly of natural polymers for SIB. The uniform nanoporous structure, remarkable mechanical properties and abundant functional groups (e.g. −COOH, −NH2 and −OH) endow the separator with lower dissolution activation energy and higher ion migration numbers. These metrics enable the separator to lower the barrier for desolvation of Na+, accelerate the migration of Na+, and generate more stable solid electrolyte interphase (SEI) and cathode electrolyte interphase (CEI). The battery assembled with the amphoteric nanofiber separator shows higher specific capacity and better stability than that assembled with glass fiber (GF) separator. [ABSTRACT FROM AUTHOR]

This contribution shares experience of teaching an interdisciplinary university course in crystal growth with examples ranging from geology to biology. This is an attempt to combine teaching the basics of the classical and non‐classical theories of crystallization with impressive examples of crystals growing around us and in the human body, as well as demonstration of the common phenomena in the growth of minerals in nature, crystalline materials in industry and the laboratory, and biomimetic and stimulus‐responsive crystals. Lectures are supported by laboratory exercises. Students can also perform an individual research project and present an oral contribution at a mini‐conference. Examples of the topics considered in the course are given, and an extensive list of references to papers and web resources is provided, which may be useful to those who want to implement anything from the authors' experience. [ABSTRACT FROM AUTHOR]

The mechanical response of printed dog‐bone specimens of poly(3‐hydroxybutyrate‐co‐3‐hydroxyhexanoate) (PHBH) in linear and nonlinear regimes is investigated. Fused filament fabrication (FFF), also regarded as fused deposition modeling (FDM), is adopted to manufacture the PHBH elements. A compressible Mooney–Rivlin constitutive law is back fitted onto digital image correlation (DIC) data, as well as uni‐axial tensile test data. Effective mechanical properties are given, which may be used to design and optimize the response of printed structures. Strain values at the verge of failure in tension are also experimentally obtained. Results are especially useful for modeling mechanical response of PHBH, which is an emerging biopolymer with promising application fields in biomedical engineering, through additive manufacturing techniques. [ABSTRACT FROM AUTHOR]

The objective of this study was to investigate the wear resistance of ultrahigh‐molecular weight polyethylene (UHMWPE) and crosslinked polyethylene (XLPE) against different counterfaces. Friction and wear studies were evaluated under dry reciprocating sliding conditions at room temperature. Ti6Al4V discs finished in polished, lapped, and ground conditions were reciprocated against polymer cylinders. In addition, abrasive wear studies were conducted using different abrasive grit sizes. The friction and wear properties of the two polyethylenes were strongly affected by the different counterfaces. XLPE showed important friction and wear sensitivity with the change of surface roughness of the Ti6Al4V disc, as well as with the change in abrasive grit size. Scanning electron microscopy and energy‐dispersive X‐ray (EDX) analysis of the worn disc surfaces and the polymer pins indicated the wear mechanisms affecting the polyethylenes. POLYM. ENG. SCI., 59:2356–2366, 2019. © 2019 Society of Plastics Engineers [ABSTRACT FROM AUTHOR]

In this paper a series of 7 salalen ligands based on an aminopyrrolidine backbone have been prepared and characterised. Several systems have been reduced to the salan ONNO type‐ligand. All ligands have been complexed to AlIII with Al(1–7)Me, Al(2a)(OiPr) and Al(7a)Me being characterised by single‐crystal X‐ray diffraction. In general the AlIII centres are best described as being in a trigonal bipyramidal geometry. The solution and solid‐state structures are discussed. All complexes have all been trialled for the production of PLA from rac‐lactide, the salalen complexes had a preference for heterotactic PLA (Pr = 0.71), whereas the salan had a more isotactic bias (Pm = 0.72). In all cases PLA with low dispersities and predictable molecular weights were prepared. The activity of the two classes of ligands is compared with the salan complexes appearing to be significantly more active than the salalen systems. [ABSTRACT FROM AUTHOR]

Product appearance is an important factor for consumers when determining the quality of a product, and colour is one of the most important factors which contribute to product appearance. Currently, the safety and consumer acceptance of some colorants used in food products, such as titanium dioxide and some synthetic colorants, are under discussion. Therefore, new ways to use natural colorants as alternatives to these suspect colorants for future applications are being investigated. A promising method for increasing the applicability of the often sensitive natural colorants is the encapsulation of these colorants in colloidal particles by natural polymers such as carbohydrates, lipids and proteins. In recent years, micro‐ and nano‐encapsulation have increasingly been used for various purposes concerning several food properties such as colour, flavour and micronutrient content. This technique results in improved stability for the often sensitive natural colorants and presents the possibility of entrapping water‐insoluble colorants for improved use in an aqueous system. This paper reviews the main methods that are used for encapsulation by natural polymers, discusses the different types thereof that are used for encapsulation of colorants, and provides a short overview of natural colorants successfully encapsulated in these natural polymers. [ABSTRACT FROM AUTHOR]

BACKGROUND: In this paper, a novel modified microcrystalline corn straw cellulose (MMCSC) was prepared by ultrasonic/microwave‐assisted treatment. Effective incorporation of MMCSC into corn distarch phosphate (CDP)‐based composite films was investigated. RESULTS: As the proportion of MMCSC was increased, tensile strength increased initially before decreasing, and the elongation at break always decreased. The composite film of MMCSC20 showed the lowest water vapor permeability (2.917 × 10−7 g m−1 h−1 Pa−1). The measurement of surface color showed that by the increasing of the MMCSC proportion in composite films, the L* and b* values and the total color difference (ΔE*) increased, while a* values decreased. Fourier transform infrared spectroscopy and X‐ray diffraction analysis indicated that, with the incorporation of MMCSC, the stable structure of the films was enhanced through cross‐linking and the crystallinity was increased. A scanning electron microscopy study revealed the surface microstructure of films (MMCSC0–MMCSC30) was smooth and homogeneous, and there was no distinct separation in the matrix of composite films. CONCLUSION: The incorporation of suitable MMCSC could improve the properties of composite films. The CDP–MMCSC films, which are completely biodegradable and environmental friendly, have a high potential to be used for food packaging. © 2018 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

From the lipopolysaccharides of Vibrio cholerae strains Inaba and Ogawa, an unusual amino sugar was isolated. By sequential oxidation with sodium metaperiodate and hypoiodide and by oxidation with periodate followed by detection of the acetaldehyde formed, the amino sugar was characterized as a 2-amino-dideoxyaldose. The hydroehloride of the amino sugar was compared with those of 2-amino-2,6-dideoxy-D-glucose, 2-amino-2,6-dideoxy-L-galactose, 2-amino-2,6-dideoxy-D-mannose, 2-amino-2,6.di-deoxy-D-gulose, and 2-amino-2,6-dideoxy-D-allose in an amino acid analyzer. The amino sugar alcohols were studied by paper electrophoresis in molybdats buffer. From the results obtained the amino sugar was identified as 2.amino-2,6-dideoxyglucose (quinovosamine). Its optical rotation indicated it to be of the D-configuration. [ABSTRACT FROM AUTHOR]

The paper presents preliminary studies of the corrosion behavior in NaCl solution of a composite made up of a conversion coating of alumina obtained by sulphuric anodization and chitosan biopolymer. The results obtained from the electrochemical studies (potentiodynamic polarization, electrochemical impedance spectroscopy) indicate a decrease of the corrosion current density for alumina–chitosan composite and a corrosion resistance improvement comparing to untreated aluminum. The presence of the alumina–chitisan composite stabilizes the passivation behavior of the anodized samples due to the sealing of the alumina pores with chitosan biopolymer. [ABSTRACT FROM AUTHOR]

Bacterial cellulose ( BC) is a promising natural polymer that is produced by bacteria and that has unique and desirable structural, physical, and chemical properties. From the time when the remarkable properties of BC were found 15 years ago compared with plant cellulose, interest has grown in BC and it has become an article of trade in diverse applications. Following this trend, this paper reviews the progress of relevant studies, including general information about cellulose, production by microorganisms as well as BC cultivation, and its properties. The applications reviewed in the present article comprise biological and nonbiological fields. The latest use of BC in the biomedical, environmental, agricultural, electronic, food, and industrial fields is discussed with its applications in composite form. The present article attempts to amass the assorted uses of BC under one umbrella. Thus, recent advances in BC applications in different fields are thoroughly reviewed. This article concludes with the need for future research of BC to make it commercialized as vital biomaterial. [ABSTRACT FROM AUTHOR]

Non‐melanoma skin cancers (NMSC) represent the most common skin tumours of the head region. We describe the use of dermal substitute in a 2‐stage surgery protocol for selected fragile patients to remove NMSC of the head region. A review of the literature focusing on dermal substitutes’ safety after skin tumours excision is provided. A total of 45 fragile patients with NMSC in the head region were selected and scheduled for the 2‐stage surgical protocol. The first stage consisted of traditional surgical excision and immediate coverage with Hyalomatrix (Fidia Advanced Biopolymers, Abano Terme, Italy). After histology confirmed diagnosis and clearance of the margins, full‐thickness skin autografts were performed. All of the patients reached complete tumour excision and wound healing. No local recurrences were registered during 24 months follow up. The 2‐stage surgical therapeutic‐diagnostic‐reconstructive approach represents a less stressful and oncologically safe surgical protocol in selected fragile patients. When patients cannot tolerate invasive and long surgical procedures, general anaesthesia, and long hospitalisation, skin grafting following temporary skin substitute coverage can achieve oncological clearance and provide good functional and aesthetic results. The use of dermal substitutes represents a valid alternative surgical option in cases of ASA III, fragile patients non‐eligible for complex reconstructive surgery. To our knowledge, this is the first paper reviewing literature focusing on dermal substitutes’ applications and safety after skin tumour excision. [ABSTRACT FROM AUTHOR]

Abstract: Cellulose possesses excellent properties, but its performance characteristics do not satisfy human requirements completely, which has soured a constant effort to improve its features. Currently, cellulose is combined with inorganics in a process called mineralization that results in a novel type of materials referred to as bio‐nanocomposites. There are many examples of mineralized tissues with superior properties in living nature. This circumstance gives us a reason to biomimic them by compounding biopolymers with inorganics. Here, the main mineralization techniques, properties, structure, functionality, and application of mineralized cellulose are the focus. Cellulose can be combined with inorganics through the vapor phase or by the methods of wet chemistry. Much attention has been paid to sol–gel chemistry, which is of first importance in cellulose mineralization. Inorganics can protect polysaccharides, regulate hydrophilicity–hydrophobicity, and impart self‐cleaning, antimicrobial and conducting properties, which not only improves them but results in bio‐nanocomposites with novel functionalities and performance, not known before for cellulosic materials. Further calcination and carbonization of mineralized cellulose under mild conditions give nanosized metals, metal oxides, and their nanocomposites with carbon, which are often unavailable by conventional methods. Therefore, mineralization is used to develop innovative textiles, oil absorbent and oil/water separating membranes, catalysts and photocatalysts, solar cells, conductors, supercapacitors, transistors and batteries for flexible electronics, and energy storage devices. These nontraditional and highly promising areas for applications have caused an intense interest in cellulose that resembles its rediscovery. [ABSTRACT FROM AUTHOR]

The finite availability of petroleum and environmental considerations has given emphasis on the development of raw materials for polymers from renewable resources. Polymers from renewable resources are expected to gain great momentum nowadays as petroleum resources become less secure. The use of biopolymer blends and composites can bring out a revolution in the field of automobile, pharmaceutical, packaging industry, etc. Poly(lactic acid) or polylactide (PLA) is the most extensively researched and utilized biodegradable and renewable thermoplastic polyester, with a potential to replace conventional petrochemical‐based polymers. Besides its relatively high tensile strength and modulus compared to other thermoplastics such as polyethylene terephthalate, polypropylene, the low impact strength and less heat tolerance of the material makes it inadequate for more demanding applications. It is the most promising material for the production of environment friendly high performance products. It is proven to be superior to conventional plastics in terms of energy consumption and carbon dioxide emission in life cycle analysis. The general purpose of this review is to introduce PLA, a compostable, biodegradable thermoplastic made from renewable sources and their blends. In the first part of this review, we briefly discuss the advantages, limitations, production methods of PLA. The second part, the major objective of this paper, focuses on the various toughening modification of PLA and also about PLA based green composites using natural fibers and agricultural residues. It also highlights the major research progress and strategies applied to improve the brittleness of polylactic acid. POLYM. COMPOS., 39:81–101, 2018. © 2016 Society of Plastics Engineers [ABSTRACT FROM AUTHOR]

Due to the ability of oils to penetrate into the structure of polymers, it is possible to create slippery surfaces with low water droplet sliding angles based on polymer coatings. Polylactic acid, polybutylene succinate and low‐density polyethylene extrusion coatings were used as such surfaces in this study. The process of penetration of vegetable oils into the polymers was studied with the subsequent investigation of slippery behaviour of such system. Cottonseed oil and castor oil showed promising properties as lubricants. For oil infused polymer surfaces the water droplet sliding angles were significantly lower than for the untreated extrusion coating. The penetration of the permeant into the upper layers of the coating was confirmed by alteration of the static water contact angle, sliding angle and also by the cross section images. LDPE extrusion coating infused with castor oil showed the lowest water sliding angle − 8°. Biopolymers, being a main focus in this study, exhibited also promising results, PLA reached sliding angle of 14° with both olive and castor oil. Dependence of polymer permeability on various factors is rather complex and the wide range of oils used in this work helps to interpret the barrier performance of the studied materials. Degree of bond saturation, viscosity and polarity were found to influence mostly on the oil permeation through the studied polymers. [ABSTRACT FROM AUTHOR]

As part of ongoing efforts to discover novel polyhydroxyalkanoate‐producing bacterial species, we embarked on characterizing the thermotolerant species, Paracoccus kondratievae, for biopolymer synthesis. Using traditional chemical and thermal characterization techniques, we found that P. kondratievae accumulates poly(3‐hydroxybutyrate) (PHB), reaching up to 46.8% of the cell's dry weight after a 24‐h incubation at 42°C. Although P. kondratievae is phylogenetically related to the prototypical polyhydroxyalkanoate producer, Paracoccus denitrificans, we observed significant differences in the PHB production dynamics between these two Paracoccus species. Notably, P. kondratievae can grow and produce PHB at elevated temperatures ranging from 42 to 47°C. Furthermore, P. kondratievae reaches its peak PHB content during the early stationary growth phase, specifically after 24 h of growth in a flask culture. This is then followed by a decline in the later stages of the stationary growth phase. The depolymerization observed in this growth phase is facilitated by the abundant presence of the PhaZ depolymerase enzyme associated with PHB granules. We observed the highest PHB levels when the cells were cultivated in a medium with glycerol as the sole carbon source and a carbon‐to‐nitrogen ratio of 10. Finally, we found that PHB production is induced as an osmotic stress response, similar to other polyhydroxyalkanoate‐producing species. [ABSTRACT FROM AUTHOR]

Black liquor is a by-product of the paper mill Kraft process that deserves more valorization than its present use as low-grade fuel. In this work, we present an original approach allowing the preparation of macroporous interconnected monolithic materials using as-received black liquor as main raw material. The process involves the formulation of an oil-in-water medium internal phase emulsion as soft templating porosity medium. The oil (internal phase) used is castor oil, whereas the continuous phase is constituted of black liquor containing a hydrophilic surfactant and epichlorohydrin as lignin crosslinking agent. Due to the high viscosity of the system, a specially designed emulsifying device was employed. The proper choices of the surfactant and emulsification conditions allow obtaining cellular biopolymers with almost monodisperse, interconnected void structure and satisfactory mechanical properties. These innovative results are promising for the future development of fully bio-based emulsion-derived materials. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013 [ABSTRACT FROM AUTHOR]

Chemical conjugation or blending with poly(ethylene glycols) (PEGs) are established procedures to facilitate solubilisation of hydrophobic compounds. The techniques of bioPEGylation and blending with PEG were applied to poly(3-hydroxybutyrate). In this paper we have examined the properties of copolymer of poly(3-hydroxybutyrate-co-poly(ethylene glycol)) (PHB-PEG) and composite material polyhydroxybutyrate with poly(ethylene glycol) (PHB + PEG) compared to homopolymer of poly(3-hydroxybutyrate) (PHB). It was found that copolymer has significally different mechanical and thermophysical properties with respect to pure PHB: an increased crystallinity but a decreased Young's modulus and elongation at break. Moreover, the creation of the composite, and a copolymer of PHB with PEG results in a change in surface morphology of ultrathin films. [ABSTRACT FROM AUTHOR]

The expanding use of electrical power generated from wind turbines and solar photovoltaic plants is enabled by the decreasing cost of electrical energy from sun and wind. With the advent of electrical energy from the intermittent solar and wind energy resources comes the requirement that electricity must be stored for use over time. The huge demand for materials for such storage systems will require a considerable energy input in extraction, processing and materials formulation, and new and sustainable electrochemical systems need to be developed. Storing electrical energy in bio based batteries is one of the options for handling the rapid expansion of renewable and variable electrical energy generated in wind turbines and in solar photovoltaic systems, from small to large. With projected needs for storage at 300 GWh for the coming decade, there are many niches for new technologies and possibilities. A supply line of materials for energy storage materials could be ultimately based on photosynthesis, in the form of materials derived from plants. Redox activity is possible in lignin, humic acid, and polyphenolic macromolecules, sometimes by electrochemical activation of redox groups. [ABSTRACT FROM AUTHOR]

Developing an advanced heterogeneous catalyst is essential for realizing high‐performance ammonia borane (AB) hydrolysis, which is a safe and efficient way to generate hydrogen. In this work, a series of ruthenium (Ru) nanoparticles (NPs) immobilized on chitosan (CS) natural polymers are synthesized via an adsorption‐in situ reduction method. Various analytical techniques, including XRD, XPS, FT‐IR, SEM and TEM, are adopted to explore the structure‐catalytic performance relationships of the obtained catalysts for hydrolysis of AB. Benefitting from the possible interaction between Ru NPs and the amino and hydroxyl groups in CS, the as‐prepared catalysts exhibit excellent catalytic behavior for hydrogen generation from AB hydrolysis. Catalyzed by the optimal Ru/CS, the turnover frequency reaches up to 331.8 min−1 in NaOH solution at 303 K, and the corresponding apparent activation energy is 41.3 kJ mol−1, which are superior to many results previously reported. This work demonstrates that the obtained Ru/CS is a promising and efficient catalyst for the hydrolysis of solid hydrogen storage materials. [ABSTRACT FROM AUTHOR]

The preparation of hydrogels for excellent sustained‐release drugs has been a focus of extensive research. In this study, lignosulfonate (LS), a kind of byproduct of papermaking, was used as a natural polymer material, acrylamide (AM) and hydroxyethyl methacrylate (HEMA) as monomers, N, N'‐methylene‐bis‐acrylamide (MBA) as cross‐linking agent, a novel LS‐based polymer hydrogels (LS‐PHGs) with pH‐responsive and excellent mechanical properties was successfully prepared by grafting copolymerization. The influence of LS on the grafting mechanism was investigated. We were pleasantly surprised to find that LS‐PHGs displayed a high swelling degree (over 20 g/g), a great loading capacity of bovine serum albumin (BSA) and obvious responsiveness for controlling drug release. Therefore, the obtained hydrogels has a promising prospect for drug delivery with excellent drug‐controlled release. [ABSTRACT FROM AUTHOR]

Natural and synthetic polymers represent a challenging source of raw materials to harvest and control in our environment. All polymeric materials eventually deteriorate and degrade over time due to changes in the inter‐ or intramolecular bonding resulting from biological and/or environmental exposure. Microorganisms use a combination of cellular hydrolytic and oxidative chemical processes to release carbon sources from polymers. Specifically, polyesters and polyurethanes are susceptible to hydrolysis by catabolic enzymes released by fungi, bacteria and archaea in the environment, and these polymer classes make up 35% of global polymer production. This review focuses on the activity of lipases, cutinases, esterases and proteases with polyesters and polyurethanes reported in articles from 2018 or later as well as new advances and key trends in both fundamental and applied biodegradation research efforts. © 2020 Society of Industrial Chemistry [ABSTRACT FROM AUTHOR]

Starch is a natural polymer that is among the sustainable materials and has the characteristics of being a green material in harmony with nature. In this study, a potential transdermal release system was evaluated by investigating 5‐fluorouracil (5‐FU) transfer through starch/poly(vinyl alcohol) (PVA) membranes in vitro. The effects of membrane thickness, starch/PVA blending ratio, pH, and temperature on the release of 5‐FU from the membranes were studied. At the end of the study, it was deduced that decrease in pH reduces the released amount of 5‐FU from starch/PVA membranes and 5‐FU transfer from membranes could be controlled within a fairly constant range. The diffusion coefficient was determined as 4.84× 10−3, 4.49× 10−3 and 2.54× 10−3 cm2 s−1 for the pH of 7.4, 5.5, and 3.5, respectively. The activation energy for the permeation 5‐FU from starch/PVA membrane (60/40, v/v) was found to be 9.72 kJ mol−1. [ABSTRACT FROM AUTHOR]

Mild acid degradation of lipopolysaccharides from Pseudomonas aeruginosa O10a and O10a,b (Lányi classification) resulted in O-specific polysaccharides built up of trisaccharide repeating units containing 2-acetamido-2,6-dideoxy-D-glucose (N-acetylquinovosamine, DQuiNAc), 2-acetamido-2,6-dideoxy-D-galactose (N-acetylfucosamine, DFucNAc), and 5-acetamido-3,5,7,9-tetradeoxy-7-[(R)-3-hydroxybutyramido]-L-glycero-L-mannononulosonic acid. The latter is a di-N-acyl derivative of a new sialic-acid-like sugar which was called by us pseudaminic acid (PseN2). A 3-hydroxybutyric acid residue was also found in natural carbohydrates for the first time. In the O10a,b polysaccharide pseudaminic acid carried an O-acetyl group at position 4. For selective cleavage of the O10a polysaccharide, solvolysis with hydrogen fluoride was employed which, owing to the relatively high stability of the glycosidic linkage of pseudaminic acid, led to the disaccharide with this sugar on the non-reducing terminus. Performing the solvolysis in methanol afforded the methyl glycoside of this disaccharide which proved to be more advantageous for further analysis. Carboxyl-reduction made the glycosidic linkage of pseudaminic acid extremely labile, and mild acid hydrolysis of the carboxyl-reduced O10a polysaccharide afforded the trisaccharide with a ketose derivative on the reducing terminus. Establishing the structure of the oligosaccharide fragments obtained and interpreting the 13C nuclear resonance spectra of the polysaccharides allowed to determine the following structure for their repeating units: → 4)DFucNAc(α1 → 3)DQuiNAc(β1 → OCHCH2CO → 7)PseN2Ac(β2 I 41 (R) CH3 OR serotype O10a R = H serotype O10a,b R = Ac In the polysaccharides the N-acetylquinovosamine residue is attached not to pseudaminic acid itself, but to its N-acyl substituent, 3-hydroxybutyryl group, and thus the monomers are linked via both glycosidic and amidic linkages. [ABSTRACT FROM AUTHOR]

Two lipopolysaccharide preparations were obtained from Escherichia coli 058 by extraction with 45% aqueous phenol and fractional precipitation with cetyltrimethyl ammonium bromide (Cetavlon). Chemical analysis and polyacrylamide gel electrophoresis in the presence of sodium dodecylsulfate showed that the two preparations differed only in the extent of the O-specific polysaccharide moiety. The O-specific polysaccharide was characterized with proton magnetic resonance and infrared spectroscopy, optical rotation and paper electrophoresis. Using gas-liquid chromatography and ion-exchange chromatography, it was shown to contain D-mannose, 2-acetamido-2-deoxy-D-glucose, 3-O-(R-1'-carboxyethyl)-L-rhamnose (rhamnolactylic acid), and O-acetyl groups in the molar ratios of 2:1:1:1. The polysaccharide and oligosaccharides obtained from it were subjected to methylation and chromic acid oxidation. The results obtained indicated that the polysaccharide consists of tetrasaccharide repeating units in which the trisaccharide β-GlcNAc1-4αMan-1-4(2/3-O-Ac)-Man is substituted at C-3 of the non-acetylated mannose with rhamnolactylic acid. The repeating units are joined through α-mannosyl-1-3-glucosamine bonds. This structure is identical with that of the cell wall polysaccharide of Shigella dysenteriae type 5. [ABSTRACT FROM AUTHOR]

Nafion has been dominating the proton exchange membrane (PEM) market because of its adequacy for the proton exchange operation. However, because of its high cost, low performance at low relative humidity, and finally environmental unfriendliness, researchers have been developing and working on Nafion alternatives. In this review, we assess how biopolymers present an opportunity as an eco‐friendly material able to replace the conventional Nafion membrane in proton exchange membrane fuel cells (PEMFC). Chitosan and cellulose were the most studied in literature owing to their abundance in nature, low cost, and high affinity for water, which are sought‐after properties for PEM. In addition to that, their ease of modification through their hydroxyl or amine groups represents an opportunity to further enhance their characteristics and thus meet the criteria of diverse applications. The use of biopolymers as an adequate PEM is facing many challenges. Having a practical proton conductivity and securing the physicochemical stability of the biopolymers in fuel cell operating conditions are two of the most important challenges to overcome. Promising strategies to simultaneously address these challenges such as crosslinking, making interpenetrated networks, and making blends and composites are reported. [ABSTRACT FROM AUTHOR]

The experiment described in this paper suggests that intravenous injections of papain produce a drooping of rabbit ears. Papain appears to deplete not only ear cartilage but also rabbit gingival tissue of acid mucopolysaccharides. Although acid mucopolysaccharides are depleted by papain, no water loss was found in the gingival tissues. [ABSTRACT FROM AUTHOR]

A linear lattice of equivalent binding sites with nearest neighbor cooperativity is used as a basic model for a linear biopolymer displaying cooperative binding of small ligands. Complicating effects due to the dimerization of free ligands are taken into account. The theory implies two types of intrinsic binding processes: (1) the binding of an isolated ligand (nucleation), and (2) the binding of a ligand in the immediate neighborhood of an already bound one (aggregation). The ratio of the respective association constants determines the degree of cooperativity. It is generally shown how the equilibrium properties of the system can be derived by means of the matrix method. Sonic properties of special practical significance, such as the equilibrium concentrations of free and bound monomer ligands, are discussed in more detail. On the basis of a pertinent kinetic model chemical relaxation of strong cooperative bindinng is also examined. The paper gives particular emphasis to the formulation of quantitative relations which are most useful for an experimental application of the the oretical results. Appropriate procedures to plot measurable data and to evaluate basic parameters are proposed. They are applied to specific experimental systems in a subsequent set of papers. [ABSTRACT FROM AUTHOR]

ABSTRACT We show how to estimate the fluid permeability changes due to accumulated biopolymer within the pore space of a granular material using laboratory measurements of overall permeability, together with various well-known quantitative measures (e.g., porosity, specific surface area, and formation factor) of the granular medium microstructure. The main focus of the paper is on mutual validation of existing theory and a synthesis of new experimental results. We find that the theory and data are in good agreement within normal experimental uncertainties. We also establish quantitative empirical relationships between seismic and/or acoustic attenuation and overall permeability for these same systems. [ABSTRACT FROM AUTHOR]

ABSTRACT The present paper reports the use of sepiolite and palygorskite fibrous clays as fillers to improve the mechanical and barrier properties of films based on neutral or negatively charged polysaccharides, such as hydroxypropylmethylcellulose, carboxymethylcellulose, alginate, pectin, and xanthan. The interaction established between the polysaccharide chains and the clay fibers, as well as the physicochemical characteristics of the resulting bionanocomposites are characterized by several techniques. These materials are processed as self-standing films that not only exhibit improved mechanical properties and water resistance, but also a significant barrier to UV light and reduced water absorption capacity, which make them very attractive for use in food packaging or coatings. Moreover, fibrous clays previously modified with the hydrophobic protein zein are also evaluated as fillers in alginate matrices, focusing on the improvement of water resistance, as well as of light and gas barrier properties, especially towards oxygen, which are of special interest for potential application in the food packaging sector. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 42362. [ABSTRACT FROM AUTHOR]