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In this contribution, a novel cellulose acetate modified with dopamine (CA-DA) membrane material was designed and prepared by a two-step route consist of chlorination and further substitution reactions. The chemical structure of the prepared CA-DA material was determined by FTIR and 1H NMR, respectively. The CA-DA ultrafiltration membrane was subsequently fabricated by the scalable phase inversion process. Compared with cellulose acetate membrane as the control sample, the introduction of dopamine improved the porosity, pore size and hydrophilicity of the CA-DA membrane, which was helpful to the water permeability (181.2 L/m2h) without obviously affecting the protein rejection (93.5%). According to the static protein adsorption and dynamic cycle ultrafiltration experiments, the CA-DA membrane displayed persistent antifouling performance, which was verified by flux recovery ratio, flux decline ratio and filtration resistance. Moreover, the water flux recovery ratio of the CA-DA membrane was retained at 97.3% after three-cycles of BSA solution filtration, which was much higher than that of the reference CA membrane. This new approach provided a long life and excellent ultrafiltration performance for polymer-based membranes, which has potential application prospects in the field of separation process.

Isocyanate is an extremely high activity compound that has been extensively used in the chemical materials. In this study, we employ microcapsules in preserving the activity of isocyanates and controlling their release in wood adhesives for plywood. Isocyanate microcapsules were synthesized by a one-step interfacial polymerization in an oil-in-water (O/W) emulsion. The particle size distribution, chemical structure, morphology, activity and stability of the obtained isocyanate microcapsules were characterized by laser particle size analyzer, n-dibutylamine titration, FTIR, SEM, and a universal strength testing machine. The as-synthesized microcapsules had approximately 25% active –NCO group and the core accounted for 77% of the total weight. The isocyanate microcapsules demonstrated satisfactory stability by preserving majority of the active –NCO group and core weight during 180 days of storage. These isocyanate microcapsules were used as functional crosslinking agent for making plywood. The resultant plywood showed higher tensile shear strength than the strength mandated in the Chinese National Standard (GB/T 9846-2015). Furthermore, the wet strength was greatly improved to meet the Class I and II plywood standards. Additionally, the stability of isocyanate microcapsules in wood adhesives were significantly enhanced for a prolonged application time. Their excellent bonding properties and stability make isocyanate microcapsules an ideal additive for use in chemical and manufacturing materials.

Purpose The purpose of the study was to prepare melamine-urea-formaldehyde (MUF) resin that would be resistant to boiling water and high temperature and exhibit low formaldehyde emission. Design/methodology/approach The authors prepared MUF resin with different F/(M + U) and changed the amount of melamine added, through the analysis of MUF resin properties to get the best reaction parameters, and used different amino acid cure systems including NH4Cl cured the resin. Findings Resin’s heat resistance and water resistance are mainly determined by the amount of melamine added, and formaldehyde emission of the plywood can be changed by adjusting F/(M + U). The peak temperature of the curing agent-cured resin increases as compared with the self-curing resin. Stronger the acidity of curing agent, faster the viscosity increased in probation period and lower the bonding strength and heat resistance of the resin. Research limitations/implications Melamine improves the heat resistance and water resistance of the resin. When the amount of melamine is more than a certain value, water resistance of the resin decreased. Practical implications MUF resin that is resistant to boiling water and exhibits low formaldehyde emission can be used in high temperature, high humidity and strict formaldehyde emission environment and can also be combined with other materials. Social implications It was helpful to reduce the effect of formaldehyde emission on people’s health and environmental pollution and is also beneficial for the expansion of the application range of aldehyde resin. Originality/value The originality is twofold: the influence of the acid strength of curing agent on the bonding strength of the resin adhesive and the method for preparing high performance MUF resin by following the traditional process.

Natural catalysts (dolomite and olivine) not only reduce the tar content, they also have a high potential to enhance hydrogen production during gasification process. In this study, a bubbling fluidized bed (BFB) was used to evaluate the effect of the operating parameters on co-gasification of pine sawdust and brown coal namely gasification temperature (Tg) in the range of 700–1000 °C, fuel particle size (dp) in the range of 2.0–3.5 mm, steam/fuel ratio (S/F) in the range of 0.5–0.8, equivalence ratio (ER) in the range of 0.1–0.4, biomass ratio (BR) in the range of 0.0–100%, and catalyst loading in the range of 3.0–12.0 wt%. With increase in catalyst loading from 3.0 to 12.0 (wt %), the hydrogen yield was increased from 52.9 to 55.5 (g/kg-fuel) for dolomite and from 47.5 to 52.1 (g/kg-fuel) for olivine, while the tar yield sharply decreased from 5.4 to 0.4 (g/Nm3) and from 7.0 to 0.8 (g/Nm3), respectively. Fuel particle size showed a negligible influence on the upgrading of hydrogen production and tar yield.

In order to compare the performance of the neat epoxy-amine network and the same network with dispersed multi-walled carbon nanotubes. The curing reaction, rheology, thermal and electrical conductivity, mechanical performance and microstructure of epoxy-amine systems were investigated in this study. The curing schedule of the epoxy-amine systems was formulated depends on the parameters of the curing reaction. The processing windows and processing time of epoxy-amine systems were provided by using rheological analysis. The thermal and electrical conductivity of epoxy-amine network with dispersed multi-walled carbon nanotubes were enhanced. The mechanical performance of the epoxy-amine network was improved after introducing the dispersed multi-walled carbon nanotubes.

This study aims to access the durability of sustainable poly (lactic acid) (PLA) composites with the presence of starch and wood flour by using artificial weathering method. Chain scissions such as photolysis and hydrolysis resulted in significant decrease in molecular weight. After artificial weathering, thermal stability decreased for all materials, but very slightly for WF/PLA composite. Both the changes of molecular weight and thermal stability revealed that the weathering rate followed the order: PLA > starch/PLA > WF/PLA, indicating that starch and wood flour improved the durability of PLA. Tensile test suggested that the PLA composites introduced in starch and WF had a better environmental survivability. At last, mathematical models were established to evaluate the decrease in tensile strength with weathering. The obtained results offer an opportunity to estimate the material's durability, and provide an idea to design sustainable PLA-based materials with enhanced durability for outdoor application.

In this paper, electrospun chitosan (CS)/poly(vinyl alcohol) (PVA)/graphene oxide (GO) nanofibers were fabricated. Prepared nanofibers have been characterized and investigated for their morphological, structural, and thermal stability, and mechanical and hydrophilic properties. The uniform and defect-free nanofibers were obtained and GO, shaping spindle and spherical, was partially embedded into nanofibers, as shown in SEM. The hydrogen bonds between CS molecules and PVA molecules were easily formed due to the great compatibility of CS and PVA. The addition of GO interrupted the hydrogen bonds between CS molecules and PVA molecules, and the new interaction was formed among CS, PVA, and GO. Thermogravimetric analysis indicated that as the increasing of content of GO, the thermal stability of nanofibers decreased. More interestingly, the static mechanical properties tests and dynamic mechanical analysis all showed that the modulus of nanofibrous mats increased firstly and decreased subsequently with the increasing of content of GO, which could be concerned with the looser arrangement of nanofibers. The water contact angle of nanofibrous mats increased with the increasing of content of GO. Nevertheless, when the content of GO was up to 2.5 wt%, the water contact angle decreased significantly.

A bis-hydroxy terminated polyphenylene oxide (MPPO) modification was tried for the purpose of simultaneously enhancing the processability and heat resistance of epoxy resin. The thermal stability, ...

To investigate the effects of acidity on aromatic yield and selectivity during the catalytic pyrolysis of biomass, the silica to alumina ratio (SAR), as well as the amount and addition method of HZSM-5 catalyst were varied. The results showed that with an increase in the SAR, the pore volume was reduced, the average pore diameter of the HZSM-5 catalyst increased, and the total acidity and catalytic activity decreased. Meanwhile, the increase in acidity led to an increased non-condensable gases yield, which was associated with a decrease in the bio-oil yield. The calorific value and moisture content increased, and the ability of deoxygenation was enhanced. The single ring aromatic hydrocarbons (BTXE) content increased, and the polycyclic aromatic hydrocarbons (2-ring, 3-ring) content decreased noticeably. The selectivity of BTXE decreased substantially from 69 wt.% to 6.85 wt.%, while the selectivity of naphthalene and its derivatives increased remarkably, as the SAR increased. Additionally, the acidity increased the selectivity of unsubstituted aromatic compounds, but decreased the selectivity of substituted aromatic compounds. Moreover, ex situ catalytic pyrolysis more effectively enhanced the aromatic hydrocarbon yield and selectivity (69 wt.%) compared with in situ catalytic pyrolysis (27.51 wt.%), and in situ catalytic pyrolysis generated more polyaromatics and solid residue.

The molecular characteristics (molar mass, hydrodynamic radius, and electrical potential) of gum arabic, corn fiber gum, and beet pectin dissolved in aqueous solutions were measured using size-exclusion chromatography and electrophoresis. Corn fiber gum and beet pectin had extended molecular structures that entrained large quantities of water, whereas gum arabic had a more compact structure. The effectiveness of the polysaccharides at increasing solution viscosity and promoting depletion flocculation decreased in the following manner: beet pectin > corn fiber gum > gum arabic. Mathematical models were used to relate differences in the molar mass and hydrodynamic radius of the polysaccharides to their ability to thicken solutions and promote depletion flocculation. There was good qualitative agreement between the models and experiments, but relatively poor quantitative agreement. The information obtained in this study may be useful for selecting appropriate natural emulsifiers to utilize in emulsion-based products.

Biodegradation behavior of biodegradable starch/wood power/polylactic acid (PLA) composites from the natural northeast Chinese soil environment was investigated in this study. The microstructural changes of the materials for 105 days was comprehensively characterized by X-ray diffraction (XRD), Differential scanning calorimetry (DSC), and Fourier transform infrared (FTIR). XRD results showed that the crystallinity of the composites increased at the initial soil burial period, followed by a decrease during the degradation period. DSC of the surface and interior of the composites at different degradation times further characterized the changes in composite microstructures. After degradation, short molecular chains were formed, which slowly gained various extents of chain mobility. FTIR analysis indicated that the random fracture sites of PLA and starch were C=O and C-O groups, respectively. The absorb intensity of C=O and C-O groups decreased with the prolonged degradation time. The P-S5W5 showed a higher degradation rate than others, likely due to the synergetic effect between starch and wood power.

Composites of poly(lactic acid) with wood flour which was grafted by melt extruding with methyl acrylate in the presence of benzoyl peroxide (BPO) were investigated. The modification of filler (WF-g-PMA) was carried out to enhance the filler-matrix interactions, while the treated component was characterized by infrared spectrum. Properties of binary (PLA/WF, PLA/WF-g-MA) composites were analyzed as a function of the grafting monomer amount by scanning electron microscopy, differential scanning calorimeter, thermogravimetric analysis, water absorption and mechanical tests. Compared with the untreated system (PLA/WF), all treated composites showed higher interfacial compatibility as a result of chemical bonding between WF and grated monomer. All composites showed higher tensile modulus and lower strength and elongation at break as compared to pure PLA; grafting modification with methyl acrylate led to an increased stiffness and decreased water absorption of the composites because of an enhanced fill...

The main objective of this work was to study aromatics production via the catalytic pyrolysis upgrading of biomass using metal-loaded modified H-ZSM-5. M-ZSM-5 catalysts were prepared through the impregnation method with Zn, Ga, Ni, Co, Mg and Cu. The prepared M-ZSM-5 catalysts were evaluated by x-ray diffraction, thermal desorption spectroscopy and scanning electron microscopy. The properties, composition and product distribution of bio-oil were also analysed. Results showed that the M-ZSM-5 catalysts yielded a higher amount of non-condensable gas at the expense of the liquid yields. The Ga-ZSM-5 catalysts produced the highest yields of bio-oil (25.76 wt%), but the lowest amount of coke (22.08 wt%) compared with the unmodified ZSM-5 catalyst (33.38 wt%). The content of the single-ring aromatics prepared by using the Zn-ZSM-5 catalysts was the highest at 90.28 wt%, whereas that of the polycyclic aromatic hydrocarbon prepared by the Ni-ZSM-5 catalysts was the highest at 31.36 wt%. Moreover, the selectivity of the single-ring aromatic hydrocarbons, such as C7 and C8, were significantly affected by the use of the M-ZSM-5 catalysts. The Zn-ZSM-5 catalysts were the most selective for toluene and xylenes with contents of 36.52 wt% and 35.32 wt%, respectively, whereas the Co-based catalysts were the most selective for indene. The Ni-based catalysts can obviously improve the selectivities of benzene production and C10+ polycyclic aromatic hydrocarbons. Zn-ZSM-5 was the most effective catalyst that can be used in the production of aromatic hydrocarbons.

Effect of accelerated weathering time and glycerol on the photodegradation behavior of starch/wood flour/PLA composites was studied. The decreased intensity of diffraction peaks characterized by XRD indicated that the crystal structure was damaged. The chemical structure changes characterized by FTIR showed the formation of carboxylic acid. The decreased extent of the C O absorbance intensity of the composite with 15% glycerol proved that glycerol had a stabilize effect on the UV durability of the composites. After weathering, the maximum decomposition temperature decreased prominently due to the chain cleavage. With the prolonged weathering time, the tensile and flexural strengths decreased gradually.

Purpose The purpose of this paper is to obtain high-solids-content and low-viscosity starch adhesive, and improve bonding strength of the pure starch adhesive. Design/methodology/approach Maize starch was treated by hydrochloric acid solution with different concentrations, and acid-thinned starch adhesive was prepared. Polyisocyanate as a crosslinking agent was added to improve water resistance of the pure starch adhesive. Findings The physical and chemical properties of the acid-thinned starch adhesive were characterised. Acid hydrolysis did not change structure of starch granules, but increased its crystallinity. After acid modification, starch granules became less smooth and some fragments appeared. Acid treatment had little influence on thermal stability of starch, when acid hydrolysis was not strong. High concentration of HCl solution led to starch granules being destroyed, resulting in decrease in bonding strength. The optimal HCl concentration was 0.5 mol/L. Polyisocyanate addition was beneficial to improve the bonding strength of the acid-thinned starch adhesive. Research limitations/implications Acid hydrolysis changed the properties of the starch adhesive. Practical implications Acid hydrolysis decreased viscosity of the starch adhesive and improved its solids content, which had a positive effect on the application of the starch adhesive. Social implications It was helpful to develop an environment-friendly, natural polymer-based wood adhesive. Originality/value The properties of acid-thinned starch and acid-thinned starch adhesive were studied.

In this paper, a benzoxazine-based (BZ) adhesive with high temperature resistant was developed by blending benzoxazine monomer and tetrafonctional epoxy monomer as matrix modifier and polyetherimide as toughening agent. The results show that benzoxazine-based film adhesive could be cured at 190 °C, and the cured film adhesive exhibited high temperature resistance and a high glass transition temperature of 224 °C. The 5% weight loss temperature in air was 400 °C and the char yield in nitrogen at 800 °C was 48%. The cured film adhesive has good ablation resistance. The fabricated benzoxazine-based film adhesive has high adhesion reliability, with single-lap shear strength of 23.20, 28.36 and 20.04 MPa at room temperature, 140 and 175 °C respectively. The curing process of the film adhesive matches well with that of carbon fiber reinforced BZ prepreg and the film adhesive has stable adhesion properties. Its biggest advantage is that, during storage and transportation, there is no need of refrigeratio...

The synthesis of structured latex particles containing hydrophilic poly(vinyl acetate) (PVAc) cores and hydrophobic poly(styrene) (PS) shells mediated by a controllable transition layer was reported. A transition layer was fabricated onto PVAc cores by introducing a coupling monomer and butyl acrylate (BA), prior to polymerization of second-stage St-based monomer mixture. While such structured PVAc/PS latex particle obtained was thermodynamic non-equilibrium, straightforward synthetic route of the transition layer can be optimized so that the particle morphology is kinetically achievable. Analysis by transmission electron microscopy shows that the particle morphology is highly influenced by both the transition layer composition and PS-based polymer composition. Two-phase particle morphology without transition layer was an inverted acorn-like structure with single PS core wrapped by PVAc shells. The particle morphology mediated by transition layer varied from that of a broken egg shell-like structure with PS-based coating, over intermediate structures in which uniform PS protuberances surrounded PVAc cores, to core/shell structure with single PVAc core. This general approach may offer a number of possibilities for design and synthesis of kinetically controllable phase-separation morphologies for a variety of applications.

Multiwalled carbon nanotubes (MWCNTs) that were treated with mixed acids were used to reinforce the cyanate ester resin. Meanwhile, the relationship among structure, morphology, and property of the modified resin was investigated. The treated MWCNTs were characterized by Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis, and X-ray photoelectron spectroscopy (XPS). The XPS results showed that the oxygen content in the treated MWCNTs was higher than that of untreated MWCNTs and the FTIR results indicated the presence of oxygen-containing functional groups on the treated MWCNTs. The microstructure of the resin was characterized by scanning electron microscopy and transmission electron microscopy. The results showed that the dispersion properties of the treated MWCNTs in the resin matrix were improved and compared with the untreated analogue. Addition of MWCNTs to the resin had little effect on the thermodynamic properties of the resin system. Upon addition of 0.8 wt% of MWCNTs to the resin, the glass transition temperature of the cured resin changed from 298°C to 285°C, maintaining a relatively high value. For the resins containing 0.6 wt% of treated MWCNTs, the plane strain critical stress intensity factor and plane strain critical strain energy release rate in the system were determined to be 1.39 Pa·m0.5 and 364 J m−2, respectively, and the fracture toughness is increased by 45.7 and 76.0%, respectively. Furthermore, the modified resin system exhibits excellent toughness and thermal properties. Therefore, the modified resin may be suitable for future applications involving high performance composites and adhesives.

Nanoemulsions are utilized within the food, pharmaceutical, and personal care industries because of their unique physicochemical properties and functional attributes: high optical clarity; prolonged stability; and, enhanced bioavailability. For many applications, it is desirable to utilize natural ingredients to formulate nanoemulsions so as to create “label-friendly” products. In this study, we compared the effectiveness of a number of natural emulsifiers at fabricating corn oil-in-water nanoemulsions using dual-channel microfluidization. These emulsifiers were either amphiphilic biopolymers (whey protein and gum arabic) or biosurfactants (quillaja saponin and soy lecithin). Differences in the surface activities of these emulsifiers were characterized using interfacial tension measurements. The influence of emulsifier type, concentration, and homogenization pressure on the efficiency of nanoemulsion formation was examined. The long-term stability of the fabricated nanoemulsions was also monitored during storage at ambient temperature. For all of the natural emulsifiers, nanoemulsions could be produced by dual-channel microfluidization, with the mean particle diameter decreasing with increasing emulsifier concentration and homogenization pressure. Whey protein isolate and quillaja saponin were more effective at forming nanoemulsions containing fine droplets than gum arabic and soy lecithin, with a lower amount of emulsifier required and smaller droplets being produced. This effect was attributed to faster emulsifier adsorption and a greater reduction in interfacial tension leading to more efficient droplet disruption within the homogenizer for saponins and whey proteins. This study highlights the potential of dual-channel microfluidization for efficiently producing label-friendly nanoemulsions from natural emulsifiers.

In this study, composites of thermoplastic poly (lactic acid) filled with wood flour (WF) were prepared via melt extrusion. Before that, alkali treatment was performed on WF to improve the properties of the WF/PLA composite materials. The effect of the solution concentrations of NaOH, namely 0.5, 1.0, 5.0, and 10.0%, on mechanical properties of the composites was evaluated. The results showed that the properties of the composites with treated WF were enhanced greatly compared with that of the untreated composites. The composites had a best improvement in its compatibility and mechanical strength when the concentration of NaOH solution was 5.0%. The brittle fracture of composites showed that the chemical modification of WFs improved the compatibility between the filler and matrix.

In this study, a new kind of membrane material, an aromatic zwitterionic polyimide (PI) copolymer, was synthesized through a one-pot polymerization reaction by precise variation of the molar ratios of different monomers with specific groups. The zwitterionic PI ultrafiltration (UF) membrane was prepared through an immersion precipitation phase inversion method and thoroughly characterized by scanning electron microscopy, water contact angle measurement, protein adsorption measurement, and UF experiment. The zwitterionic PI membrane showed significantly improved hydrophilicity and permeability and stable antifouling property. The amount of bovine serum albumin adsorbed on the zwitterionic PI membrane was considerably lower compared with the reference PI membrane. According to the cycle UF experiment for protein solution, the zwitterionic PI membrane had a water flux recovery ratio of 86.7%, compared with only 61.1% for the reference PI membrane. Moreover, the irreversible fouling of the zwitterionic PI membrane was significantly decreased, suggesting superior antifouling property. This new approach to the preparation of a zwitterionic polymer seems promising for potential applications in separation membrane.

A one-component, non-crosslinked, and ambient temperature-cured core/shell (CS) structured waterborne poly(styrene-acrylate) (PStA) latex adhesive was prepared by two-stage seeded emulsion polymerization. The first-stage polymers were non-polar styrene-based copolymers with Tgs ranging from 86 °C to 41 °C and the second-stage polymer was polar acrylate-based copolymer having a Tg of 8 °C. The effect of latex particle morphology and film microstructure on the CS structured PStA latex adhesive was examined by evaluating film thermal properties and mechanical performance. The results have shown that incorporation of soft shell polymers into hard core polymers can improve adhesive properties without compromising film-forming ability. Wood adhesive performances of latex adhesive were measured by shear strength and boiling water resistance of glued wood blocks. The utilization performances of the one-component CS structured PStA latex adhesive were found to largely depend on CS morphological character and the interfacial compatibility between various polymeric constituents, demonstrating that fabrication of CS latex particles provides a promising approach to realize high-performance latex adhesives.

•PVA has a significant effect on improving the toughness of UF foam.•Cell shape was seen to be elongated in the rise direction with the addition of PVA.•Release of HCNO, CO2, NH3 was detected in the gaseous product of PVA modified UF foam during pyrolysis.

In order to overcome the large differences in reactivity ratio and hydrophilicity between vinyl acetate (VAc) monomer and styrene (St) monomer and synthesize a stable poly(vinyl acetate)/polystyrene (PVAc/PS) inverse core/shell (ICS) structural emulsion, this paper presented a novel method to prepare PVAc/PS ICS structural latex particles. Maleic anhydride (MA) grafting, for the first time, was introduced to fabricate the ICS latex particles, where VAc monomer was used as the core monomer and St monomer as the shell monomer. By adjusting the core/shell (CS) ratio and MA content, the morphology of the particles could be controlled to have a regular evolution from strawberry-like to semi-wrapped and final ball-like. In addition, upon MA content exceeding 1 % (percentage of the total monomer), the secondary nucleation almost disappeared gradually. The resulting ICS particles had an average diameter approximately 330 nm and a controllable distribution. Further results of characterization such as phase separation structure, existence of thin transition layer, and special morphological feature of latex particle also demonstrated that this ICS structure had been fabricated successfully. The mechanism of formation was displayed as well.

The application of liquid isocyanate in composite material is limited because of its high activity and toxicity. In this work, microcapsules were employed to preserve the activity of isocyanates. The liquid isocyanates were also solidified which allowed them to be easily added to the Polylactic acid/wood flour (PLA/WF) to enhance the properties by controlling the release of isocyanate. The stable isocyanate microcapsules (IM) were synthesized by minimalist complex coacervation without extra crosslinker. The properties of IM and composites were studied by chemical titration, Fourier Transform Infrared (FTIR) spectroscopy, Particulate Size Analysis (PSA), Thermogravimetric Analysis (TGA), Scanning Electron Microscopy (SEM), etc. The results showed that the prepared IM were approximately 200 μm in diameter, the active content was around 25% and the core accounted for 80% of the total weight. When the amount of IM added was 2.5%, the tensile strength, Young's strength and bending strength of the composite increased by 23.2%, 46.4% and 22.0% respectively compared with pure PLA. The impact strength increased by 52.3% compared with the composite without isocyanate microcapsules. Furthermore, IM improve the stability of isocyanate, suggesting the promising application of IM in various building materials.

Notably, zwitterionic polymers have attracted increasing attention to various potential applications in membrane-based separation processes on account of the good biocompatibility, superior antifouling and excellent antimicrobial property. In this contribution, a novel membrane material based on zwitterionic poly(aryl ether oxadiazole) (Z-PAEO) was designed and synthesized by a facile and convenient two-step route consist of polycondensation and quaternary amination reaction. Z-PAEO ultrafiltration membrane was subsequently fabricated by the scalable non-solvent induced phase separation (NIPS) method. The chemical structures and compositions of these prepared polymers were determined by using 1H NMR, FTIR and XPS measurements, and their inherent viscosities, molecular weights, thermal properties and solubility behaviors were extensively characterized, respectively. The presence of zwitterionic groups considerably improved the porosity, pore size and hydrophilicity of Z-PAEO membrane, which was helpful to the permeability of the obtained membrane without obviously affecting the protein rejection. Interestingly and significantly, the as-prepared Z-PAEO membrane displayed superior and persistent antifouling performance as well as antibacterial property. The water flux recovery ratio of Z-PAEO membrane (97.6%) after a three-cycles of BSA solution filtration was much higher than that of the reference PAEO membrane (78.4%), suggesting excellent long-term performance stability. It can be expected that developing novel zwitterionic polymers can significantly expand the application scopes of separation membrane.

PVAc-based inverted core/shell (ICS) structured latex adhesive with improved water- and heat-resistance was prepared by a copolymerizing-grafting sequential reaction approach. The sequential reaction process combines the function of a copolymer layer and an active grafting site to controllably achieve the thermodynamic non-equilibrium ICS morphology with hydrophilic poly(vinyl acetate) (PVAc) cores and hydrophobic polystyrene (PS) shells. The difference between the sequential reaction approach and the chemical grafting method was explored. Structured latex particle morphology, transferring from strawberry-like particles, over particles with large and irregular PS protuberances, to nearly spherical particles with a smooth surface, was microscopically visualized by changing the amount of butyl acrylate (BA) in the PVAc copolymer cores. The heat- and water-resistant bonding of PVAc-based adhesives on wood blocks were evaluated by shear strength at both dry and wet conditions, as well as the boiling water failure time. The results showed that a significant improvement of water- and heat-resistance, especially for boiling water resistance, was successfully obtained. This novel approach paves a way for controlled design and manufacture of high-performance emulsion adhesives through tailoring particle morphology.

Strategy for fabricating inverted core/shell (ICS) structured latex particles to improve the water- and heat-resistance of PVAc-based adhesives was investigated. A grafting layer was fabricated with acrylonitrile (AN) to achieve a thermodynamic non-equilibrium ICS morphology with a hydrophilic poly(vinyl acetate) (PVAc) core and a hydrophobic polystyrene (PS) shell. The function of the grafting layer was explored by tuning the AN loading levels and core-to-shell ratios. Special latex particle morphologies, transferring from strawberry-like with secondary PS particles, over neat strawberry-like, to final ball-like morphology, were observed and verified by electron microcopies. The wood adhesive performance of PVAc-based latex adhesives, particularly for heat- and water-resistant bonding, were evaluated by shear strength at both dry and wet conditions, as well as the boiling water failure time, showing a significant enhancement of boiling water resistance. This general approach opens an avenue for controlled design and manufacture of high-performance emulsion-based adhesives containing structured particles.

In this study, vitamin E was encapsulated in oil-in-water nanoemulsions fabricated using a dual-channel microfluidizer. A long chain triacylglycerol (corn oil) was used as a carrier oil and a biosurfactant (quillaja saponin) was used as a natural emulsifier. The impact of vitamin-to-carrier oil ratio on the formation, storage stability, and bioaccessibility of the nanoemulsions was determined. The lipid droplet size formed during homogenization increased with increasing vitamin content, which was attributed to a large increase in lipid phase viscosity. The storage stability of the nanoemulsions decreased as the vitamin content increased because the larger lipid droplets creamed faster. The rate and extent of lipid hydrolysis in the small intestine decreased as the vitamin content increased, probably because the vitamin molecules inhibited the ability of lipase to reach the triacylglycerols inside the lipid droplets. Vitamin bioaccessibility decreased as the vitamin level in the lipid phase increased, which was attributed to the reduced level of mixed micelles available to solubilize the tocopherols. The optimized nanoemulsion-based delivery system led to a relatively high vitamin bioaccessibility (53.9%). This research provides valuable information for optimizing delivery systems to increase the bioaccessibility of oil-soluble vitamins.

Four different biorenewable methacrylated/acrylated monomers, namely, methacrylated fatty acid (MFA), methacrylated eugenol (ME), isobornyl methacrylate (IM), and isobornyl acrylate (IA) were employed as reactive diluents (RDs) to replace styrene (St) in a maleinated acrylated epoxidized soybean oil (MAESO) resin to produce bio-based thermosetting resins using free radical polymerization. The curing kinetics, gelation times, double bond conversions, thermal–mechanical properties, and thermal stabilities of MAESO-RD resin systems were characterized using DSC, rheometer, FT-IR, DMA, and TGA. The results indicate that all four RD monomers possess high bio-based carbon content (BBC) ranging from 63.2 to 76.9% and low volatilities (less than 7 wt% loss after being held isothermally at 30 °C for 5 h). Moreover, the viscosity of the MAESO-RD systems can be tailored to acceptable levels to fit the requirements for liquid molding techniques. Because of the introduction of RDs to the MAESO resin, the reaction mixtures showed an improved reactivity and an accelerated reaction rate. FT-IR results showed that almost all the C[double bond, length as m-dash]C double bonds within MAESO-RD systems were converted. The glass transition temperatures (Tg) of the MAESO-RDs ranged from 44.8 to 100.8 °C, thus extending the range of application. More importantly, the Tg of MAESO-ME resin (98.1 °C) was comparable to that of MAESO-St resin (100.8 °C). Overall, this work provided four potential RDs candidates to completely replace styrene in the MAESO resin, with the ME monomer being the most promising one.

In this paper, chitosan (CS)/graphene oxide (GO) composite films were prepared, and the effect of γ-ray irradiation on the properties of composite films was investigated. The irradiation crosslinking reaction occurred in composite films with the existence of acetic acid, and the properties changed upon the various irradiation dose. The swelling degree of the composite film with 0 wt % GO decreased with the increasing of the irradiation dose, but the swelling degree of which with GO increased instead. The thermal stability increased with the increasing of the irradiation dose, but the effect of the irradiation on the thermal stability weakened as the increasing of the content of GO, due to the enhanced irradiation resistance performance. The tensile strength increased firstly and decreased subsequently with the increasing of the irradiation dose and the content of GO. Composite films showed the enhanced antibacterial activity against Bacillus subtilis, compared to Escherichia coli and Staphylococcus aureus. The antibacterial activity weakened with the increasing of the content of GO. The antibacterial activity was relatively stronger when the irradiation dose was 20 KGy. In addition, the structural, crystal, and morphological properties of composite films were characterized by FT-IR, XRD, and SEM. It is worth noting that the GO was pre-functionalized via KH560 for the better compatibility with CS matrix.

A renewable chemical, eugenol, is methacrylated to produce methacrylated eugenol (ME) employing the Steglich esterification reaction without any solvent. The resulting ME is used as a low viscosity comonomer to replace styrene in a commercial epoxy-based vinyl ester resin (VE). The volatility and viscosity of ME and styrene are compared. The effect of ME loadings and temperatures on viscosity of the VE-ME resin is investigated. Moreover, the thermo-mechanical properties, curing extent, and thermal stability of the fully cured VE-ME thermosets are systematically examined. The results indicate that ME is a monomer with low volatility and low viscosity, and therefore the incorporation of ME monomer in VE resins allows significant reduction of viscosity. Moreover, viscosity of the VE-ME resin can be tailored by adjusting ME loadings and processing temperature to meet commercial liquid molding technology requirements. The glass transition temperatures of VE-ME thermosets range from 139 to 199 °C. In addition, more than 95% of the monomer is incorporated and fixed in the crosslinked network structure of VE-ME thermosets. Overall, the developed ME monomer exhibits promising potential to replace styrene as an effective low viscosity comonomer. The VE-ME resins show great advantages for use in polymer matrices for high performance fiber-reinforced composites. This work showed great significance to the vinyl ester industry by providing detailed experimental support.

Soil burial degradation was confirmed to be an efficient waste disposal method for the biodegradable materials with short service life, such as starch/poly (lactic acid) (PLA) composite. The biodegradation behavior about chemical and thermal properties of starch/PLA composite was analyzed by using X-ray photoelectron spectroscopy (XPS), infrared microscopy (IRM), differential scanning calorimetry (DSC), and thermal gravimetric analysis (TGA). XPS and IRM results indicated that the biodegradation of PLA occurred at the ester groups in PLA chains. XPS demonstrated the cleavage of CO linkages between glucose rings in starch. DSC and TGA results showed that the starch/PLA composite degraded faster than the pure PLA. During the soil burial degradation, the glass transition temperature of starch/PLA composite exhibited an obviously decrease while it had a slight variation for PLA. The thermal stability of starch/PLA composite shifted towards to that of PLA when they were subjected to soil burial for the same time. It is established that the starch can accelerate the degradation of PLA-based materials, which will enlarge the markets of biodegradable PLA materials used for short service life products.

A novel strategy for fabricating inverted core-shell structured latex particles was implemented to investigate the morphology and properties of polyvinyl acetate (PVAc)-based latex. In this study, active grafting points were synthesized onto the surface of PVAc latex cores via grafting acrylonitrile (AN) to obtain a controllable coating growth of the shell monomer, styrene (St). The effect of shell growth on the morphological evolvement was explored by tuning the time of shell monomer polymerization. Unique particle morphologies, transferring from “hawthorn„ type, over “peeled pomegranate„ type, to final “strawberry-like„ type, were observed and verified by electron microscopy. The morphological structure of latex particles exerted a significant effect on the particle size, phase structure, and mechanical properties of the obtained emulsions. The water-resistance of PVAc-based latex was also evaluated by the water absorption of latex films. More importantly, the experimental results provided a reasonable support for the controlled growth of St monomer, that is, the self-nucleation of dispersive St monomer can be transformed to in-situ coating growth on the PVAc core surface depending on the AN-active grafting points. This fabricating approach provides a reference for dynamical design and control of the latex particle morphology.

Starch-based adhesives were prepared by esterification modification with dodecenyl succinic anhydride (DDSA) and polyaryl polymethylene isocyanate (PAPI) as a crosslinking agent. DDSA modified starch (DMS) adhesives could significantly enhance the viscosity and adhesion strength of starch adhesives, making it beneficial to be applied in the field of plywood industry. This paper investigated the physicochemical properties of starch modified by dodecenyl succinic anhydride. Solid content, viscosity, adhesion, structural change and morphological features were characterized in detail. Viscosity and solid content of the modified starch (MF) adhesives was improved remarkably when DDSA was introduced. Three-ply plywood was fabricated with DMS adhesives, and its wet shear strength was measured. The results showed that the water resistance of the adhesive with 6wt% DDSA improved by 72.4% compared to that without DDSA. The wet shear strength plywood bonded by the adhesive reached 1MPa and could meet the requirement set by the China National Standard. Incorporating DDSA into the starch adhesive formed a dense crosslinking structure due to chemical reactions between DDSA and active groups on the starch molecules and thus improve the water resistance of the cured adhesives. The introduction of DDSA improving the viscosity and solid content remarkably, which increased the amount of the adhesive that penetrated the wood surface and formed more interlocks. Using DDSA promoted a smooth and homogeneous fracture surface of cured adhesive, which effectively prevented water intrusion and improved water resistance. The modified adhesive proved practical as a plywood adhesive for industrial application.

A novel, bio-based, aromatic monomer (methacrylated vanillyl alcohol, MVA), was synthesized using vanillyl alcohol and methacrylic anhydride in the absence of solvents. The resulting MVA was characterized and used as a sustainable reactive diluent to replace styrene in a maleinated acrylated epoxidized soybean oil (MAESO) resin to produce novel thermosetting resins via free radical polymerization. The influence of MVA loading (10 - 40%) on the viscosity, gelation time, curing extent, thermo-mechanical properties, and tensile properties of the MAESO-MVA copolymer was investigated. The synthesized MVA exhibited very low volatility relative to styrene, which is beneficial for the development of construction material with low or zero emission. With 40 wt% of MVA content in MAESO, a significant reduction of system viscosity (over an order of magnitude) was achieved. Increasing the MVA content accelerated the crosslinking reaction rate and improved thermal and mechanical properties of the MAESO-MVA system. The glass transition temperature increased with increasing MVA content. Soxhlet extraction experiments showed that more than 90% of the components were incorporated into the crosslinking network. The effect of MVA purity on the properties of the resulting copolymer was also investigated. MAESO-MVA copolymers prepared using high-purity MVA exhibited higher degree of crosslinking.

The biodegradation behavior of Poly (lactic acid) (PLA) blended with starch and wood flour in outdoor soil was investigated comprehensively. As a result, starch provided a biological fuel for the growth of microorganisms in the soil which accelerated the degradation rate of PLA more obviously than wood flour. With the increase of starch content, the weight loss increased and the morphology exhibited more gullies and cavities. X-ray Photoelectron Spectroscopy (XPS) analysis indicated that the variation of O/C ratio was controlled by starch biodegradation and PLA hydrolysis and they were a concomitant process. The mechanical strengths of all the blends showed similar trend and fitted a first-order exponential decay model. The model is shown in good agreement with experimental results as the correlation coefficient is higher than 0.99, and the model can support an efficient method to estimate the durability of starch/wood flour/PLA blends.

To improve prospects for high-value utilization of biomass, torrefaction pretreatments were conducted at 210, 230, 250, 270, and 300 °C with a reaction time of 30 min. The pyrolysis of torrefied biomass was also performed on a fixed-bed reactor system at 450 °C. The effect of torrefaction temperature on the yield, energy yield, structure, physical-chemical characteristics, and production composition of bio-oil was studied. The torrefaction pretreatment improved the fuel characteristics of pyrolysis products. When the torrefaction temperature was increased, the -OH and C=O contents decreased, the C=C contents increased, the pyrolysis peak temperature decreased, the residual carbon contents noticeably increased, and the Ea value remained in the range of 69 to 129 kJmol-1. The pore volume increased and the crystallinity index decreased due to degradation and recrystallization. The solid yield of pyrolysis biomass decreased sharply in contrast to the liquid yield. When the torrefaction temperature increased, the bio-oil yield decreased from 36.82 wt.% to 20.13 wt.%. The phenol content in the bio-oil markedly increased; however, oxygen-containing compounds such as acids, sugars, and furans, significantly decreased, which indicated that torrefaction pretreatment efficiently improved the quality of the fuel.

Maleated thermoplastic starches (MTPS) were prepared by reactive extrusion, with corn starch as raw material, glycerol as the plasticizer, and maleic anhydride (MAH) as esterification agent. The influence of the amount of MAH on MTPS properties was studied. With thermoplastic starch (TPS) as contrasting sample, Fourier transform infrared spectroscopy results displayed that esterification reaction successfully occurs between corn starch and MAH. The degree of substitution (DS) results showed that the DS of MTPS increased along with the increasing amount of MAH. X-Ray diffractometry results showed that esterification reaction resulted in the decrease of crystallinity of TPS, indicating that the thermoplastic property of starch was improved. The greater the proportion of MAH, the more decreased is the degree of crystallinity of MTPS. Differential scanning calorimetric results showed that the melting temperature and enthalpy of melting decreased with increasing the amount of MAH. The thermal weight loss initial temperature of MTPS was below TPS, and thermal weight loss rate was greater than TPS. The contact angle of MTPS was greater than TPS, while the water absorption of MTPS was less than TPS. Further, with increasing of MAH content, the contact angle increased, while water absorption decreased, which indicated that the hydrophobic was gradually improved.

A normal temperature cured starch-based wood adhesive was prepared using dry method esterification and polyisocyanate prepolymer crosslinking. The effects of esterification and crosslinking on the properties of corn starch adhesive were investigated. The esterified starch and adhesive were characterized using Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), dielectric analysis (DEA), thermogravimetric analysis (TGA), and scanning electron microscopy (SEM). The results showed that maleic anhydride (MAH) esterified starch was obtained using dry method esterification. After esterification, the crystal type of starch did not change, but the crystallinity of starch decreased. The distribution of adhesive at the bonding interface was improved after esterification. The prepolymer improved the thermal stability of the adhesive, and the optimal addition of prepolymer was 10%.

Plasticized poly (lactic acid) (PPLA) was prepared by melt blending poly (lactic acid) (PLA) with 10 wt% of poly (ethylene glycol) (PEG), with varied molecular weights range from 400 to 4000. The structure, thermal property, morphology, and surface free energy of the PPLA were investigated by Fourier transform infrared spectroscopy (FTIR), differential scanning calorimeter (DSC), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), and contact angles (CA). The resulting PPLA results indicated that the introduction of PEG to the blend systems resulted in a ductile fracture, a decrease in the melt temperature (Tm) and glass transfer temperature (Tg), and an increase in the degree of crystallization (χc), which indicated an improved flexibility. In addition, the polarity of the PPLA increased and the surface free energy decreased. The resulting PPLA was subsequently used as matrix to blend with wood flour to prepare composites. The mechanical strength, melting behavior, thermal stability, and microscopy of the PPLA/wood flour composites were also evaluated. These results illustrated that the plasticized PPLA matrix was beneficial to the interfacial compatibility between the polar filler and the substrate.

MA modified wood flour/PLA composites were prepared by one-step reactive extrusion, in which wood flour and poly(lactic acid) (PLA) were used as raw material, maleic anhydride (MA) was used as modifier, and dicumyl peroxide (DCP) was used as initiator. The influences of MA concentration on the morphology, thermal stability, rheological, and mechanical properties of the composites were studied. The addition of MA improved the compatibility of the composites significantly. The thermal and rheological results showed that with the increase of the concentration of MA, the thermal stability of the composites decreased, the storage modulus and complex viscosity of the composites also decreased. The MA modified composites had an enhanced mechanical strength compared to the unmodified one. As the concentration of the MA increased, the tensile and flexural strength of the composites first increased and then decreased, and reached a maximum when the concentration of MA was 1 wt %. The MA modified composites showed a better water resistance than the unmodified ones. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43295.