Valorization of Camellia oleifera oil processing byproducts to value-added chemicals and biobased materials: A critical review

The C.oleifera oil processing industry generates large amounts of solid wastes,including C.oleifera shell(COS)and C.oleifera cake(COC).Distinct from generally acknowledged lignocellulosic biomass(corn stover,bamboo,birch,etc.),Camellia wastes contain diverse bioactive substances in addition to the abundant lignocellulosic components,and thus,the biorefinery utilization of C.oleifera processing byproducts involves complicated processing technologies.This reviewfirst summarizes various technologies for extracting and converting the main components in C.oleifera oil processing byproducts into value-added chemicals and biobased materials,as well as their potential applications.Microwave,ultrasound,and Soxhlet extractions are compared for the extraction of functional bioactive components(tannin,flavonoid,saponin,etc.),while solvothermal conversion and pyrolysis are discussed for the conversion of lignocellulosic components into value-added chemicals.The application areas of these chemicals according to their properties are introduced in detail,including utilizing antioxidant and anti-in-flammatory properties of the bioactive substances for the specific application,as well as drop-in chemicals for the substitution of unrenewable fossil fuel-derived products.In addition to chemical production,biochar fabricated from COS and its applications in thefields of adsorption,supercapacitor,soil remediation and wood composites are comprehensively reviewed and discussed.Finally,based on the compositions and structural characteristics of C.oleifera byproducts,the development of full-component valorization strategies and the expansion of the appli-cationfields are proposed.

Curing Kinetics of Tannin and Lignin Biobased Adhesives Determined by DSC and ABES

The curing process of two biobased adhesives:pine tanninhexamine(TH)and organosolv lignin non-isocyanate polyurethane(NIPU),suitable for interior nonstructural use,were compared with commercial urea-formaldehyde(UF)adhesive.Changes in chemical structure before and after the curing process were observed with Fouriertransform infrared spectroscopy(FTIR).The process of adhesive curing was monitored with differential scanning calorimetry(DSC)and the automated bonding evaluation system(ABES).Both DSC and ABES measurements confirmed UF as the fastest and NIPU as the slowest curing adhesive observed.Taking into account the ABES results,the optimal pressing parameters for the TH adhesive would be 4 min at 175℃,for the NIPU adhesive 7 min at 200℃and for the UF 1.5 min at 100℃.Strong linear correlation was observed between mechanical and chemical curing for the UF and NIPU adhesives,whereas lower correlation was observed for the TH adhesive.At all observed adhesives,the DSC measurements were underestimating the curing process determined by ABES in the first part and overestimating it at the end.The underestimation was the most evident with the TH adhesive and the less with the UF adhesive.When comparing the uncured and cured FTIR spectra of all three types of adhesives,a drastic decrease in the characteristic band of-OH groups at 3330–3400 cm^(−1)and an increase in the signal intensity at 2920 cm^(−1)of aliphatic-CH2-groups were observed.For the UF adhesive,the C=O stretching frequency has shifted from 1632 cm^(−1)for uncured to three different bands at 1766,1701,and 1655 cm^(−1)for cured UF.The sharp band for phenolic alcohols at 1236 cm^(−1)of C–O stretch and hydroxyl O–H functional group at 1009 cm^(−1)and at 684 cm^(−1)of uncured TH adhesive diminished during curing,which indicates that a crosslinking reaction occurs via-OH groups.The peak of the C=O group of urethane bridges at 1697 cm^(−1)for uncured NIPU shifted to lower wavenumber at 1633 cm^(−1)for cured NIPU.

Insights into biobased epoxidized fatty acid isobutyl esters from biodiesel:Preparation and application as plasticizer

Biodiesel was used to prepare epoxidized fatty acid isobutyl esters(Ep-FABEs)as a biobased plasticizer in this work.Transesterification of biodiesel with isobutanol catalyzed by tetrabutyl titanate was carried out in a gas-liquid tower reactor.The conversion achieved nearly 100%within 5 h under the reaction temperature,the mass ratio of catalyst to fatty acid methyl esters(FAMEs),and isobutanol to FAMEs total molar ratio of 180℃,0.4%(mass),and 5.4:1,respectively.In addition,kinetic model of the transesterification reaction was developed at 150–190℃.The calculated activation energy was 48.93 kJ·mol^(-1).Then,the epoxidation of obtained fatty acid isobutyl esters(FABEs)was conducted in the presence of formic acid and hydrogen peroxide.The Ep-FABEs was further analyzed for its plasticizing effectiveness to replace dioctyl phthalate(DOP)and compared with conventional epoxy plasticizer epoxidized fatty acid methyl esters(Ep-FAMEs).The results indicated that the thermal stability and mechanical properties of PVC films with Ep-FABEs plasticizer were significantly improved compared with those plasticized with DOP.In addition,the extraction resistance and migration stability of Ep-FABEs were better than those of EpFAMEs.Overall,the prepared Ep-FABEs via structural modification of biodiesel proved to be a promising biobased plasticizer.

Biobased Vanillic Acid and Ricinoleic Acid: Building Blocks for Fully Renewable Copolyesters

New fully biobased polyether/esters have been synthesized by a one-pot polymerization reaction of ricinoleic acid(RA),vanillic acid(VA)and ethylene carbonate(EC).In particular,EC selectively reacts with the phenolic group of VA to obtain in-situ 4-(2-hydroxyethoxy)-3-methoxybenzoate(EV),suitable for subsequent copolymerization with RA.The procedure was carried out in a single step,without any solvent.Chemical structure and thermal properties of the new materials were studied in order to explore relationships between composition and final performances.The combination of EV,bearing a rigid aromatic structure,with RA,characterized by high flexibility and potential biocidal activity,allows the production of a novel class of fully biobased aliphatic-aromatic polymers presenting tuneable thermal properties and suitable for a range of applications,for example,in active packaging and biomedical fields.

Polyhydroxyurethanes from Biobased Monomers and CO_(2):A Bridge between Sustainable Chemistry and CO_(2) Utilization

Polyhydroxyurethanes(PHUs)have received considerable attention in the last decade as potential alternatives to traditional phosgene-based polyurethanes(PUs).The development of suitable 5CC(five membered-ring cyclic carbonate)precursors bearing multiple carbonate moieties(multi-5CCs)is a key requisite for preparing PHUs by polyaddition reaction with bis-or polyamines.Producing sustainable PHUs from CO_(2)-based five-membered cyclic carbonates(5CCs)obtained from biobased epoxides is a valuable strategy to bridge CO_(2) utilization and the upcycling of renewable substrates.In this context,while many multi-5CC monomers reported in the literature are oil-based,recent efforts have led to the development of a large variety of multifunctional 5CCs that are produced by the combination of CO_(2) and renewable resources such as fatty acids and vegetable oils,lignin,terpenes,and sugars.In this work,recent crucial advances(2019—2023)on PHUs prepared from bis-and multi-5CCs produced from CO_(2) and(partially/potentially)biobased substrates are reviewed with respect to their synthesis,thermal and mechanical properties,and their recent,emerging applications.

BIOBASED PRODUCTS AND THE LEED® RATING SYSTEM

At the beginning of the 20th century,over 40%by weight of all the materials consumed through the production of goods within the United States were comprised of renewable resources(Matos and Wagner 1998).In contrast,by the end of the 20th century renewable material usage had dropped to less than 8%by weight(Matos and Wagner 1998).Combined with both an increase in the overall rate at which we consume resources as well as growing awareness of the inherently finite availability of nonrenewable resources,the early decades of the 21st century may mark the beginning of a shift back to an increased use of biobased materials.While the relative proportion of the demand for biobased materials has changed over the past century,one factor that has remained constant is that a majority of renewable and nonrenewable resources consumed in the U.S.is used in the construction industry(Matos and Wagner 1998).Although the utilization of biobased products is increasing throughout all sectors,their popularity still lags in the building and construction industry,and they are surpassed by more widely accepted green practices such as the use of pre-and post-consumer recycled materials.There is,however,a great potential benefit to be gained from a resurgence in the use of biobased products,both from general environmental and human health perspectives.Examples of specific sectors that may profit from this include building and construction industries,which account for 40%(Roodman and Lenssen 1995)of global raw material usage,as well as the Federal government,which is the largest real property owner in the U.S.(U.S.General Services Administration 2006).A biobased material is defined as containing some percentage of a biologically renewable resource.According to ASTM E2114-2004,a renewable resource is something“that is grown,naturally replenished,or cleansed,at a rate which exceeds depletion of the usable supply of that resource.”The length of time needed to replace a renewable resource can vary greatly depending upon the resource-for example,it can take 30-100 years for a tree to mature while bamboo can be harvested in as little as 7 years.Rapidly renewable resources are defined,for the purposes of this paper,as those that can be replaced within 10 years.Bamboo,linoleum,and cork are just a few of the more common examples of rapidly renewable resources.The renewable,biobased,component of a material is either derived from a plant or animal,and resource supplies are typically managed in a sustainable fashion,thus ensuring its continued availability.This material may then be used within the product in a fairly unaltered state,it may undergo some chemical or physical transformation,or it may be combined with other products to create an intermediate ingredient in the production or manufacturing process.The decrease in biobased material utilization over the last 100 years has led to an increased use of non-biobased materials,and this development can yield numerous potentially negative impacts that have been fairly well docu­mented in terms of many of their environmental impacts such as eutrophication and air pollution.These,however,only account for a portion of the total sum of potential impacts.In addition to potentially harmful impacts on the exterior environment,various material ingredients and components can negatively affect the interior environment as well through the release of volatile organic compounds(VOCs)and other types of indoor air pollutants.VOCs are a concern because their emissions can be an ongoing problem within an interior space,since in addition to the initial release of compounds,surfaces can continually absorb and re-release the compounds back into the environment where they are absorbed by the inhabitants.If this occurs in combination with other problems,like poor building air circu­lation,the potential can develop for more serious concerns such as“Sick Building Syndrome”(U.S.Environmental Protection Agency 2010).While some of this can be mitigated through improved ventilation,indoor air quality is still found to be a concern by the U.S.Environmental Protection Agency(Indoor Air Quality,2010)and other groups.One of the most well known indoor air contaminants is formaldehyde,which is commonly found in the adhesives used in pressed wood products such as furniture,shelving,or particleboard;finishes and coatings on fabrics;paints and coatings;as well as some types of insulation.3 A 2008 study by Papadopoula,Nakos,and Tsiantzi examined the replacement of the formaldehyde-based resins with certain renewably based ones that yielded equivalent,and in some cases superior,performance characteristics in addition to providing a reduction in VOC levels.Another study that investigated school cleaning products found that,on average,the contaminate emission rate for green general cleaners was one fifth that of conventional cleaners(Environmental Working Group 2009).Other studies too,have shown correlations between the use of petroleum-based products and increased VOC levels.A joint report by the Healthy Building Network and Health Care Without Harm(Silas,Hansen,and Lent,2007)also promotes the use of renewable materials to lessen indoor air quality concerns,and it provides guidelines and information for the health care industry on the benefits of renewable and biobased materials as well as the poten­tial issues associated with petrochemical-based fibers.Additionally,the Healthy Building Network offers biopolymer and bioplastic production and purchasing guidelines.These environmental and health related concerns,as well as the potential market for biobased products,have become the focus of a variety of different areas of legislation and development.In addition to numerous Federal initiatives,an increased awareness of biobased materials and products is also being fostered within the building and construction fields by building rating systems such as Energy Star®,Green Globes,and Leadership in Energy and Environmental Design(LEED®).

Biobased polyurethanes for biomedical applications

Polyurethanes(PUs)are a major family of polymers displaying a wide spectrum of physico-chemical,mechanical and structural properties for a large range of fields.They have shown suitable for biomedical applications and are used in this domain since decades.The current variety of biomass available has extended the diversity of starting materials for the elaboration of new biobased macromolecular architectures,allowing the development of biobased PUs with advanced properties such as controlled biotic and abiotic degradation.In this frame,new tunable biomedical devices have been successfully designed.PU structures with precise tissue biomimicking can be obtained and are adequate for adhesion,proliferation and differentiation of many cell’s types.Moreover,new smart shape-memory PUs with adjustable shape-recovery properties have demonstrated promising results for biomedical applications such as wound healing.The fossil-based starting materials substitution for biomedical implants is slowly improving,nonetheless better renewable contents need to be achieved for most PUs to obtain biobased certifications.After a presentation of some PU generalities and an understanding of a biomaterial structure-biocompatibility relationship,recent developments of biobased PUs for non-implantable devices as well as short-and long-term implants are described in detail in this review and compared to more conventional PU structures.

Preparation of Degradable Polymenthide and Its Elastomers from Biobased Menthide via Organocatalyzed Ring-opening Polymerization and UV Curing

Development of degradable polyester elastomers plays an important role in the applications of soft mateirals.Noncrystalline polymenthides(PMs)from menthol derived lactone monomers are excellent soft segments for preparing degradable polyester elastomers.By using cyclic trimeric phosphazene base(CTPB)as an organocatalyst,we succesfully synthesized PMs with different molecular weights(8.2 kDa to 100.7 kDa)in high yields via ring-opening polymerization(ROP)of menthide.When a CTPB/urea binary catalytic system was adopted,the polymerizations proceeded in a more controlled manner.Using glycerol as initiator,star shaped PMs with well.defined structure were synthesized and subsequently end-capped by acrylate.UV iradiation of the terminal acrylate groups in the star-shaped PMs resulted in formation of chemically cos-linked polyester elastomers without heat or other stimuli.The obtained polyester elastomers exhibit matched modulus(3.8-5.5 MPa),tensile strength(0.56-0.68 MPa),and strain at break(280%-320%)with soft body tssues,displaying great potential in biomedical applications.

Biobased materials for food packaging

Consumers prefer foods that are healthier with high quality and safety.Food packaging are de-manded to effectively extend the shelf-life,preserve the nutrients and decrease the microbial contamination during the transport and storage of food.With the increasing concern on the envi-ronmental impacts caused by food packaging wastes,sustainable and green packaging are highly demanded to minimize the harmful effects of food packaging waste on the environment.Bio-based materials are derived from sustainable and renewable biomass,instead of finite petrochemicals.The applications of bio-based materials for food packaging are highlighted in this review.The emphasis is placed on the categories of related biobased materials,their characteristics and ad-vantages for food packaging,as well as the strategies used to improve their performances.Though a lot of trials have been done on biobased materials for food packaging,further attempts to im-prove their performances,understand the functioning mechanisms and develop greener methods for the production,processing and destiny of these bio-based materials are still highly needed for the future research.

Bio-based polymeric materials synthesized from renewable resources: A mini-review

In recent years,bio-based polymeric materials have attracted increased attention owing to their distinctive prop-erties,including richness,sustainability,environmental friendliness,and biodegradability.This article reviews the recent developments and potential trends of research on bio-based polymers synthesized from various re-newable resources.It covers the resources and structures of bio-based monomers,the methods of synthesis and properties of bio-based thermoplastics and thermosets,the production of bio-based composites and the fabrica-tion of functional bio-based polymers.Finally,the technological and future challenges related to enabling these materials to apply in the industry have been discussed,together with the potential solutions or directions.

Synthetic Process of Bio-Based Phenol Formaldehyde Adhesive Derived from Demethylated Wheat Straw Alkali Lignin and Its Curing Behavior

Lignin is a natural biopolymer with a complex three-dimensional network, commercially obtained from wasteliquid of paper pulp and bioethanol production, and could be a candidate for preparation of environment-friendlybio-based polyphenol material. In the present work, the demethylated wheat straw alkali lignin (D-Lig), preparedby demethylation of wheat straw alkali lignin (Lig) using an in-situ generated Lewis acid, was used to synthesizebio-based phenol formaldehyde resin adhesive (D-LPF) applied in plywood. Effects of synthetic process’s factors,including lignin substitution for phenol, NaOH concentration and molar ratio of formaldehyde to phenol, on thebonding strength and free formaldehyde content of D-LPF were investigated in detail, and the optimum syntheticprocess of D-LPF was obtained as following: Lignin substitution for phenol 60%, NaOH concentration 5.0% andmolar ratio of formaldehyde to phenol 2.0, and under the optimum reaction condition, the D-LPF presented lower free formaldehyde content (0.18%) and higher bonding strength (2.19 MPa), which was better than those ofcontaining-lignin phenol formaldehyde resin adhesive (LPF). Additionally, the curing behavior of the adhesivewas studied by differential scanning calorimetry (DSC) combined with gel time. It can be obtained that D-LPFresin adhesive had the shortest gel time, and fastest curing rate, compared with those of PF and L-PF resin adhesives. The curing kinetics data was fitted well by Kissinger model using non-isothermal DSC method, and theaverage activation energy value was 85.3 kJ/mol, slightly higher than that of commercial PF resin, while lowerthan that of LPF (90.2 kJ/mol). Finally, based on the analytical results of high temperature fourier transform infrared spectroscopy (FTIR), a possible curing mechanism of D-LPF was proposed.

Novel Bio-based Flame Retardant Systems Derived from Tannic Acid

In this study,tannic acid(TA)was investigated as flame retardant agent for PLA.Different strategies to modify its thermal degradation pathway have been explored in order to improve its charring effect.The first one consists in combining TA with organomodified montmorillonite(oMMT),and enables limiting the thermo-oxidative degradation of TA and promoting the formation of an effective char layer.Flame-retardant(FR)behavior of PLA-based composition has been found to be positively impacted by this combination since a reduction of the peak of Heat Release Rate(PHRR),more important than the value recorded when oMMT and tannic acid are used separately,has been obtained.The second strategy,in which tannic acid was associated with a biosourced phosphorousbased compounds,i.e.metallic phytate salt,evidenced another alternative allowing enhancing TA flame retardant effect at 30 wt%loading content.The third and last strategy explored aims to chemically modify TA via a chemical grafting of phosphoric acid groups.This phosphorylated TA was shown to present the most effective flame-retardant(FR)effect.However,an important reduction of PLA molecular weight was observed.

Green biomanufacturing promoted by automatic retrobiosynthesis planning and computational enzyme design

Biomanufacturing,which uses renewable resources as raw materials and uses biological processes to produce energy and chemicals,has long been regarded as a production model that replaces the unsustainable fossil economy.The construction of non-natural and efficient biosynthesis routes of chemicals is an important goal of green biomanufacturing.Traditional methods that rely on experience are difficult to support the realization of this goal.However,with the rapid development of information technology,the intelligence of biomanufacturing has brought hope to achieve this goal.Retrobiosynthesis and computational enzyme design,as two of the main technologies in intelligent biomanufacturing,have developed rapidly in recent years and have made great achievements and some representative works have demonstrated the great value that the integration of the two fields may bring.To achieve the final integration of the two fields,it is necessary to examine the information,methods and tools from a bird’s-eye view,and to find a feasible idea and solution for establishing a connection point.For this purpose,this article briefly reviewed the main ideas,methods and tools of the two fields,and put forward views on how to achieve the integration of the two fields.

Shear Strength and Morphological Study of Polyurethane- OMMT Clay Nanocomposite Adhesive Derived from Vegetable Oil-Based Constituents

In the current work,we have synthesized vegetable oil-based polyurethane-OMMT clay nanocomposite(PUNC)adhesive with the incorporation of different wt%of organically modified nanoclay(1 to 5 wt%)into the biobased polyurethane(PU)matrix through in-situ polymerization process via ultrasonication method.At the initial stage,PU adhesive was prepared using polyol and partially biobased aliphatic isocyanate,wherein polyol was derived from the transesterified castor oil using ethylene glycol.The formation of PU and PUNC adhesive was confirmed using Fourier transform infrared(FTIR)spectroscopy analysis.The tensile strength of PU with different wt%of nanoclay was determined and the analysis showed that the loading of 3 wt%of nanoclay within the PU matrix showed better performance as compared to the others.Furthermore,shear strength of PU and PUNC(3 wt%nanoclay)adhesives were determined using lap shear test,in which PUNC adhesive showed higher adhesive strength at 70°C.Subsequently,the dispersibility of OMMT nanoclay within the PU matrix along with exfoliation and amorphous structure was confirmed through wide angle X-ray diffractometer(WAXD)and transmission electron microscopy(TEM)analysis.The phase separation structure was analyzed using dynamic mechanical analysis(DMA).The analysis revealed that with the addition of organically modified nanoclay in the PU matrix,the glass transition temperature(Tg)of the damping curve was shifted towards higher temperature.

Highly Functional Polyol Synthesis from Epoxidized Tall Oil Fatty Acids

In this work, free tall oil fatty acids were epoxidized with in-situ generated peroxyacetic acid. Reaction kineticsof epoxidation was investigated by oxirane content and iodine value titrimetric determination, as well as FTIRspectra analysis. A highly functional biobased polyol was synthesized by functionalizing epoxidized tall oilfatty acids with triethanolamine using Montmorillonite K10 as a catalyst. The obtained polyol was analyzed byFTIR and MALDI-TOF MS. The most common chemical and physical characteristics of obtained polyol weredetermined.

Melt Extrusion of Environmentally Friendly Poly(L-lactic acid)/Sodium Metabisulfite Films for Antimicrobial Packaging Applications

Food packaging materials compounded with antimicrobial additives can substantially diminish the incidence of foodborne diseases.Here,poly(L-lactic acid)(PLA)films containing sodium metabisulfite(NaM)were produced by melt extrusion as an attempt to develop a new biodegradable material with antimicrobial properties for packaging.Life cycle assessment(LCA)simulations revealed that the environmental footprints of the PLA film did not change upon NaM addition,and that NaM is more eco-friendly than silver nanoparticles.The PLA/NaM films with NaM content varying from 0.5 to 5.0 wt.%were characterized by differential scanning calorimetry(DSC),thermogravimetric analysis(TGA),and optical and mechanical properties determinations.The optical properties were sustained after the addition of NaM,but high NaM contents degraded the light transparence of the PLA matrix at some extent.The thermal stability and tensile properties of the PLA film decreased proportionally to the NaM content,while no changes were observed on Tg,Tm and Xc,as determined by DSC.Agar diffusion tests revealed that the PLA/NaM films had no antimicrobial activity on Saccharomyces cerevisiae at 35°C,which was related to the limited migration of NaM from the glassy PLA matrix.The biodegradable PLA films compounded with NaM through melt extrusion display adequate optical,thermal,and mechanical properties to cover most food packaging applications,representing an essential step toward the development of eco-friendly packaging materials that can potentially exhibit an antimicrobially active surface.

Estimating potential harvestable biomass for bioenergy from sustainably managed private native forests in Southeast Queensland, Australia

Background： Australia＇s energy future is at the crossroads and the role of renewable sources is in focus. Biomass from sustainably managed forests provide a significant opportunity for electricity and heat generation and production of liquid fuels. Australia has extensive native forests of which a significant proportion are on private land. However, there is limited knowledge on the potential capacity of this resource to contribute to the expansion of a biomass for bioenergy industry. In addition, there are concerns on how to reconcile biomass harvesting with environmental protection. Methods： We used regional ecosystem vegetation mapping for Queensland to stratify harvestable forests within the 1.8 m hectares of private native forests present in the Southeast Queensland bioregion in 2014. We used a dataset of 52,620 individual tree measurements from 541 forest inventory plots collected over the last 10 years. Tree biomass was estimated using current biomass allometric equations for Australia. Biomass potentially available from selective sawlog harvesting and silvicultural treatment across the bioregion was calculated and mapped. Results： Current sawlog harvesting extracts 41.4% of the standing tree biomass and a biomass for bioenergy harvest would retain on average 36% of felled tree biomass on site for the protection of environmental and fauna habitat values. The estimated area extent of harvestable private native forests in the bioregion in 2013 was 888,000 ha and estimated available biomass for bioenergy in living trees was 13.6 million tonnes （t）. The spotted gum （Corymbio citriodora subsp, variegata） forests were the most extensive, covering an area of 379,823 ha and with a biomass for bioenergy yield of 14.2 t-ha-1 （with approximately 11.2 t.ha-1 of the biomass harvested from silvicultural thinning and 3 t.ha-1 recovered from sawlog harvest residual）. Conclusions： Silvicultural treatment of private native forests in the Southeast Queensland bioregion, has the capacity to supply a large quantity of biomass for bioenergy. The availability of a biomass for bioenergy market, and integration of sawlog harvesting and silvicultural treatment operations, could provide land owners with additional commercial incentive to improve the management of private native forests. This could potentially promote restoration of degraded forests, ecological sustainability and continued provision of wood products.

Two Routes to Produce Chitosan from Agaricus bisporus

Two methods were used to produce chitosan by deacetylation of chitin which was extracted from Agaricus bisporus stipes.The first one gives chitosan 1 with low yield of 2.5%,degree of acetylation(DA)of 4%,molecular weight(MW)of 2.973×10^(5)(g/mol).The second route produces chitosan 2 with higher yield of 41%,degree of acetylation(DA)of 17.23%,molecular weight(MW)of 2.939×10^(5)(g/mol).Both chitosans were characterized by XRD,FTIR,^(1)H-NMR spectroscopy nuclear magnetic resonance of proton.The molecular weight(MW)was determined by size exclusion chromatography(SEC).Thermal analysis shows that both chitosans have moisture content lower than 10%.However chitosan 2 has the less ash%which is the quality grade for chitosan medical applications.Accordingly,fungal chitosan 2 could have potential medical and agricultural applications.

Synthesis and Characterization of the Thermoelectric Nickel Tetrathiooxalate Polymer as Nanoparticles

Nanoparticles of the conductive coordination polymer Ni(tto) have been synthesized under mild conditions in the presence of bio-based polyesters or polyethylene glycol acting as growth controlling agents. With polyesters, aggregates of particles are observed whereas well dispersed nanoparticles are obtained with polyethylene glycol. Indeed, for a Ni2+/polyethylene glycol weight ratio of 0.031, transmission electron micrographs evidence dispersed particles exhibiting sizes in the 3 - 10 nm range. Infrared spectra for nanopowders show two CS stretching modes in the 1100 - 1190 cm−1 range, confirming the presence of the tetrathiooxalate ligand coordinated to the nickel center. The room-temperature electrical conductivity for the nanopowder prepared in the presence of polyethylene glycol is about 0.8 S∙cm−1, a decent value for tetrathiolate-based polymers. Finally, magnetic susceptibility measurements for well-dispersed Ni(tto) particles evidence a Curie-Weiss law in a large temperature range. Moreover, low temperatures measurement would confirm intra- or interchain interactions between nickel atoms within the Ni(tto) polymer chains.

Hair Dyeing by Using Catechinone Obtained from (+)-Catechin

A novel colourant for hair dyeing was prepared by an enzymatic reaction with (+)-catechin and its characteristics as a hair dyestuff were studied. The study is aimed at inventing the hair dyestuff that is human- and eco-friendly. One potentially powerful dyestuff was obtained from (+)-catechin treated with tyrosinase after screening experiments using biobased materials. The obtained reddish orange colourant, 4-(3,4-dihydro-3α,5,7-trihydroxy-2H-1-benzopyran-2α-yl) 1,2-benzoquinone named “catechinone”, shows enough dyeability for decolourised white hair. Catechinone does not cause erythema or oedema on skin of rabbits. The colour is controlled by the addition of other biobased materials and a variety of colours of dyed hair are acquired. The fastness to light or washing for hair dyed by catechinone is high enough for practical use.