Wheat gluten (WG) shows great promise to synthesize environment-friendly wood adhesives. However, their weak bonding strength and poor water resistance have limited its application in the commercial wood-based panel industry. In this study, a novel WG-based adhesive was developed by constructing a multiple crosslinking network generated by covalent and non-covalent bonds. The potential mechanism was revealed by FTIR analysis. Furthermore, their surface morphology, thermal stability, viscosity, and residual rate of adhesives with different compositions were systematically characterized and compared. The results showed that the hydrogen bonding, reactions between amine groups and tannin, and ring opening reaction of epoxy, synergistically contributed to generate a highly crosslinked network. The wet/boil water strength of the plywood prepared from WG/tannin/ethylene imine polymer (PEI)-glycerol triglycidyl ether (GTE) adhesive with the addition of 15 % GTE could reach 1.21 MPa and 1.20 MPa, respectively, and a mildew resistance ability was observed. This study provides a facile strategy to fabricate high-performance plant protein-based adhesives with desirable water resistance for practical application.

Lignin oligomers were prepared by ultrasonic-assisted depolymerization using corn cob lignin as raw material. The effects of depolymerization conditions on the yield and relative molecular mass of lignin oligomers were investigated, and the lignin oligomers were characterized by gel permeation chromatography(GPC), infrared spectroscopy(FT-IR), two-dimensional nuclear magnetic resonance spectroscopy (2D-HSQC NMR) and nuclear magnetic resonance phosphorus spectroscopy (31P NMR). The results showed that the yield of resultant lignin oligomer reached 40.2% and the number-average molecular weight ( Mn) of obtained lignin oligomer was 710 under the conditions of ultrasonic treatment (frequency 40 kHz, power 240 W) for 3 h and the solid-liquid ratio of lignin to solvent 200:1(g: L) in methanol/water (4:1, v: v) solvent system. The polydispersity index (PDI) was 1.62, which reserved the main molecular structure units of lignin, and the total hydroxyl content was 10.49 mmol/g.

The sulfonated lignin-based chain transfer agent(SL-CTA) was synthesized using pre-sulfonated corn stover lignin, followed by the functional modification of xanthate carbon disulfide and methyl bromoacetate. The SL-CTA was used in the aqueous RAFT polymerization of acrylamide to prepare sulfonated lignin-acrylamide copolymer(SL-g-PAM). Various methods were used to characterize the chain transfer agents and copolymers. The results showed that the arylsulfonation modification was more effective than the sulfomethylation modification. The best modification effect was achieved when 1g of lignin was reacted with 2 g of chlorosulfonic acid at 25 ℃ for 4 h, where the S concentration in sulfonated lignin was 1.83%, the ratio of Mw/ Mn was 1.19, the amount of total hydroxyl groups was 4.86 mmol/g, and the water solubility was good. The chemical structure of the SL-CTA was then investigated by FT-IR and 13C NMR. The results showed that the stretching vibration absorption peak of C—S bond at 900 cm-1 and the characteristic peak at 1 738 cm-1 relating to C=O group were found in the FT-IR spectrum, and the peak at δ 172 corresponding to carbon atom of the C=S appeared in the 13C NMR spectrum, proving the successful synthesis of the chain transfer agent. In addition, the effects of the ratios of monomer/chain transfer agent/initiator, pH value and reaction temperature on the monomer conversion in the aqueous RAFT polymerization system of acrylamide were investigated. The results showed that the conversion rate was as high as 98.5% when the ratio of monomer/chain transfer agent/initiator was 500∶4∶1, pH value was 5, reaction temperature was 70 ℃ and reaction time was 4 h. Under the experimental conditions, the first-order kinetic curve of the polymerization reaction showed a good linear relationship, and the relative molecular mass of the obtained polymer also presented a linear relationship with the monomer conversion rate. At the same time, its polydispersity index was low and the distribution was relatively narrow(1.13-1.43), which all indicated that the reaction had high controllability.

As the richest aromatic renewable resource, lignin has attracted significant attention for fabricating various materials.

Developing lignin-based flame retardants for phenolic foam with exceptional flame retardancy and mechanical performances remains a huge challenge due to complicated chemical structure and unstable chemical activity of lignin. In this study, nitrogen‑phosphorus doped lignin flame retardant (NP-LMDL) was prepared by modifying reactive lignin with 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) and triethylenetetramine (TETA), which was utilized to partially replace phenol to prepare flame retardant phenolic foams (NP-LMDLPFx). The results showed that nitrogen‑phosphorus doped lignin enhanced the flame retardant performance and compressive strength of the foam. The limiting oxygen index (LOI) and compressive strength of NP-LMDLPF15 increased by 33.3% and 43.7% comparing with pure phenolic foam (PF). The peak heat release rate (pHRR) and peak smoke release rate (pRSR) decreased by 48.0% and 53.2%. Moreover, the structure and elemental constitution of char residues were analyzed to discuss the flame retardant mechanism of nitrogen and phosphorus in foam. Nitrogen and phosphorus in NP-LMDLPFx worked together to promote polymers carbonization and generate rich nitrogen and phosphorus char residue layer, insulate heat and oxygen to play the role of flame retardant.

Magnetic hydrogels have been widely utilized in the fields of biomedical devices, flexible electronics, and soft robotics. Unfortunately, current strategies to synthesize magnetic hydrogels are difficult to achieve high mechanical properties. Herein, we have presented a biomimetic strategy to synthesize a strong, tough and elastic cellulose enhanced magnetic hydrogel (CEMH). The cellulose skeleton containing magnetic nanoparticles was first generated by self-assembly of cellulose chains as the enhancement filler, while elastic polyacrylamide formed by in situ polymerization functioned as the elastic matrix. The mechanical and physicochemical properties of CEMH, as well as the effect of Fe 3 O 4 and acrylamide concentration on the performance, were systematically investigated. The highest tensile strength and toughness of CEMH could reach 1.1 MPa and 2.9 MJ/m 3 , respectively. Furthermore, CEMH showed a high elastic recovery of 94.5% (10th cycle), accompanies by a certain swelling resistance ability. All these advantages were accomplished mainly owing to the synergetic contribution of biomimetic design and enhanced non-covalent interactions.

采用曼尼希反应,将玉米芯木质素改性制备木质素胺(AL),然后与水性聚酰胺(PAE)、聚乙二醇二缩水甘油醚(PEGDE)混合,以豆粕粉为原料,通过AL/PAE/PEGDE改性制备高固体含量的豆粕基胶黏剂(豆胶).对豆胶性能进行表征和测试,结果表明:复合改性豆胶固化后的红外谱图中酰胺Ⅰ带吸收峰由1632 cm-1处蓝移至1640 cm-1,酰胺Ⅱ带吸收峰由1533 cm-1蓝移至1538 cm-1,此现象说明固化豆胶中形成了结构致密相互交联的网状结构;热重分析结果也说明PAE、PEGDE、AL与蛋白质分子之间形成了结构更为致密的网络结构;流变行为分析显示固化豆胶具有假塑性流体的特征;改性豆胶含固体高达42.5％,而表观黏度仅为3 746 mPa·s,具有较好的涂布性能,适于工业化应用;所得胶合板的胶合强度为0.86 MPa,合格率100％,符合国家Ⅱ类胶合板的标准要求(胶合强度≥0.70 MPa,合格率≥90％).

A novel adsorbent of ZrO2/PEI/Fe3O4 functionalized MWCNTs composite (MWCNTs@Fe3O4@PEI-Zr) possessing a high affinity to phosphate and easily separated from aqueous solution was proposed in this work. The ZrO2 and PEI modified on the surface act as active sites for the removal of phosphate, while the Fe3O4 allows for the easy separation by applying an external magnetic field. Compared to traditional separation like centrifugation, magnetic separation markedly reduces energy consumption and provides more possibilities for application. The composite exhibits a relatively high surface area of 162.9 m2 g-1 with a larger number of mesopores. As-prepared MWCNTs@Fe3O4@PEI-Zr is found to have a relatively high phosphate adsorption capacity of 21.14 mg P g-1 and it can be recovered rapidly from water under an external magnetic field. Moreover, MWCNTs@Fe3O4@PEI-Zr exhibits an outstanding anti-interference capability in terms of the coexisting ion and ionic strength of solutions. Importantly, the dissolution of Zr and Fe are negligible (less than 0.015 mg L-1) over a wide pH range of 4.04-9.98, indicating that the MWCNTs@Fe3O4@PEI-Zr is a structurally stable hybrid composite particle with strong interaction. Furthermore, it shows a good reusability and 86.2% removal efficiency of phosphate remains after three consecutive cycles. Both the ligand exchange and the electrostatic attraction are mainly responsible for phosphate removal by MWCNTs@Fe3O4@PEI-Zr. This work demonstrated that the highly efficient, easy separable, high stability and reusability MWCNTs@Fe3O4@PEI-Zr composite has the potential for phosphate removal.

The utilization of biomass resource to fabricate multi-functional thermoset elastomer with full recyclability and high stretchability is desirable but remains challenging. Herein, a cellulose reinforced thermoset elastomer with excellent recyclability and stretchability is designed to address this challenge. To fabricate the thermoset elas-tomer, the cellulose macro-crosslinker bearing maleimide group was utilized to react with the furan modifying poly(styrene-block-butadiene-block-styrene) (SBS) through thermally reversible Diels-Alder (DA) reaction to construct the dynamic crosslinked thermoset elastomer. The formation of dynamic crosslinked network was demonstrated by stress relaxation, swelling, and DMA tests. Importantly, the formation of the dynamic cross -linking network not only improved the mechanical property, but also endowed the thermoset elastomer with thermal recyclability and solid-state plasticity, and the recycling efficiency was 88.1 %. Furthermore, the recyclable thermoset elastomer composite doping with CNT showed excellent and reliable photothermal con-version and Joule heating performance, and the surface temperature of the composite film rapidly reached 126.3 degrees C under the voltage of 7.5 V by Joule heating. These thermoset elastomer composites showed promising applications in the fields of photoelectric generators and rapid deicing coating.

Controllable fabrication of lightweight, highly conductive, and flexible films is important to simultaneously achieve excellent electromagnetic interference (EMI) shielding and high-rate energy storage. Herein, ultrathin, flexible, and conductive (up to 365,000 +/- 5000 S m(-1)) TOCNFs/CNT/Ti3C2Tx hybrid films were fabricated by a facile vacuum-filtration. The obtained films with 60 wt% Ti3C2Tx content exhibited a high specific EMI SE of 9316.4 +/- 205.32 dB cm(2) g(-1), which was comparable to most of the other carbon-and MXene-based materials synthesized by complex steps. Additionally, the porous structure contributed to exposing more active sites and providing efficient transport of electrolyte ions. Consequently, the hybrid films showed a high areal capacitance and high specific capacitance of 537 mF cm(-2) and 279.7 F g(-1) at 0.3 mA cm(-2), respectively, together with impressive stability of 93.1% after 8000 cycles. This work provides an effective strategy to synthesize high-performance conductive films for applications in wearable or portable electronic devices.

通过FTIR、元素分析、GPC对4种不同来源的木质素磺酸钠进行物理化学性质分析,并将其与水性聚酰胺协同改性豆粕胶黏剂(简称豆粕胶),利用测试接触角、剪切黏度和湿态胶合强度考察改性前后胶黏剂的浸润性、流变特性以及所得胶合板的胶合性能.红外谱图分析表明,在1065 cm–1附近出现了磺酸基或磺甲基中S==O的伸缩振动吸收峰,证明木质素经过磺化反应或磺甲基化反应得到木质素磺酸钠;木质素磺酸钠中磺酸基含量越高,经其改性的豆粕胶的零剪切黏度越低且在木材表面的润湿性越好;豆粕胶黏剂与杨木单板的接触角从未改性的95°降到改性后的61°;与水性聚酰胺协同改性后的豆粕胶制得胶合板的湿态胶合强度达到0.92 MPa,合格率为100％,满足国家Ⅱ类胶合板的标准要求(胶合强度≥0.70 MPa,合格率≥90％).

Conversion of solar energy into thermal energy stored in phase change materials (PCMs) can effectively relieve the energy dilemma and improve energy utilization efficiency. However, facile fabrication of form-stable PCMs (FSPCMs) to achieve simultaneously energetic solar–thermal, conversion and storage remains a formidable challenge. Herein, we report a desirable solar–thermal energy conversion and storage system that utilizes paraffin (PW) as energy-storage units, the silver/polypyrrole-functionalized polyurethane (PU) foam as the cage and energy conversion platform to restrain the fluidity of the melting paraffin and achieve high solar–thermal energy conversion efficiency (93.7%) simultaneously. The obtained FSPCMs possess high thermal energy storage density (187.4 J/g) and an excellent leak-proof property. In addition, 200 accelerated solar–thermal energy conversion-cycling tests demonstrated that the resultant FSPCMs had excellent cycling durability and reversible solar–thermal energy conversion ability, which offered a potential possibility in the field of solar energy utilization technology.

The conversion of cornstalk lignin derived from the co-product of bio-refinery into value-added products such as polymeric material has remarkable environmental and economic potential. A novel bio-based methyl methacrylate copolymerized with butyl acrylate (MMA-co-BA) hybrid resin in our research was prepared by the reversible addition–fragmentation chain transfer method using lignin-graft-polyacrylamide (lignin-g-PAM) as a bio-derived macromolecular chain transfer agent. The molecular architecture of lignin-g-PAM and the lignin-based MMA-co-BA hybrid resin was elucidated using 1H nuclear magnetic resonance and attenuated total reflectance–Fourier transform infrared. The thermal behavior and mechanical performance of the resultant lignin-based MMA-co-BA hybrid resins were also investigated through thermogravimetric analysis, differential scanning calorimetry, and a stress–strain test, respectively. The lignin-based acrylate resins system exhibited structure-related thermal and mechanical properties. Compared with pure MMA-co-BA resin, the incorporation of lignin into various lignin-based MMA-co-BA graft copolymers resulted in an improved tensile strength and a higher Young’s modulus. This research could provide not only a new avenue to utilize waste biomass for high-value applications, but also a reference for designing new materials for coatings or adhesives.

以木质素黄原酸酯为链转移剂,进行丙烯酰胺(AM)的可逆加成-断裂链转移(RAFT)自由基聚合,并将得到的木质素-丙烯酰胺接枝共聚物(Lignin-g-PAM)作为大分子链转移剂,加入第二单体甲基丙烯酸甲酯(MMA)进行扩链反应制备木质素基嵌段共聚物(Lignin-g-PAM-b-PMMA).红外光谱 、核磁共振氢谱 、凝胶渗透色谱 、差示扫描量热及热重分析结果证实了MMA与Lignin-g-PAM反应形成了嵌段共聚物;所得Lignin-g-PAM-b-PMMA的相对分子质量显著增加,相对分子质量分布变宽,初始分解温度及最大质量损失温度提高,玻璃化转变温度介于Lignin-g-PAM与PMMA的玻璃化转变温度之间.

利用饲料级大豆粉为原料,通过水性聚酰胺和异氰酸酯对其进行协同复合改性制备出具有良好流变行为和固化性能的大豆胶黏剂.采用旋转流变仪研究了复合改性剂用量对大豆胶黏剂流变行为和固化性能的影响,结果表明:改性后的大豆胶黏剂属于假塑性流体,当水性聚酰胺添加量为10％时,所得大豆胶黏剂的流变性能较优,而异氰酸酯添加量对大豆胶黏剂的流变行为几乎没有影响;运用动态温度扫描模式研究大豆胶黏剂的黏弹性能,异氰酸酯添加量对大豆胶黏剂的储能模量和损耗模量影响较大.水性聚酰胺/异氰酸酯协同交联体系可与大豆蛋白分子间发生交联,当10％水性聚酰胺和4％异氰酸酯协同改性时,所得胶合板的胶合强度可达0.74 MPa,满足国家Ⅱ类胶合板使用要求(≥0.70 MPa).

采用一锅法,以木质素为原料,经二硫化碳、2-溴丁酸甲酯进行黄原酸酯功能化改性合成木质素基大分子链转移剂(lignin-CTA),通过FT-IR、1H NMR、13C NMR对其结构进行表征,并将其用于丙烯酰胺的RAFT聚合反应制备木质素-丙烯酰胺共聚物(lignin-g-PAM),考察该反应的聚合特征.木质素功能化改性前后的红外谱图显示:改性后羟基吸收峰明显减弱,并且在1148和1732 cm-1处分别出现了—C—S键振动吸收峰和酯键的羰基吸收峰,说明2-溴丁酸甲酯已成功接枝到木质素大分子上;同时lignin-CTA的1H NMR谱图中于δ0.90处出现了2-溴丁酸甲酯末端甲基的活泼氢质子峰,13C NMR谱图中于δ162处出现了—C—S的碳原子峰,进一步印证了接枝反应的进行.丙烯酰胺的RAFT聚合反应结果显示:聚合物的相对分子质量与转化率基本呈现线性关系,同时其多分散系数较低且分布相对较窄(1.26～1.53),证明该聚合反应具有高效可控特性.

The research advances of laser cutting technology were first stated. Then to study the performance of bamboo laser cutting and obtain the optimum technological parameters, we used a laser cutting machine with 60 W power laser tube and observed the magnified kerf shape. We found laser cutting perpendicular to the fiber direction was more difficult than other cutting directions under the same conditions. The notch depth was the deepest by parallel cutting and the notch width was the widest by oblique cutting. When the thickness of laser-cut bamboos was 3 mm, we obtained moderate kerf width, thinner carburization zone and better kerf quality under laser nozzle height 20 mm, cutting speed 30 m.min(-1) and laser output power 48 W, which were the optimum technological parameters of bamboo laser cutting.

In order to improve the quality of sliced thick veneers and to reduce the hydrothermal treatment time,a veneer slicer with the function of real-time steam injection heating was used for slicing experiment of eucalyptus.This experiment was conducted under the four kinds of softening conditions,namely,soaking in cold water,steam heating after soaking in cold water,water-boiling and steam heating after water-boiling.The surface roughness of veneers were 4.29-14.30 μm,and increased gradually with the increase of slicing thickness,the surface roughness perpendicular to grain was larger than that parallel to grain,but all of them could meet GB/T 13010-2006.The change of back clearances tended to be smooth when the slicing thicknesses were 5-6 mm.Compared with the condition of non-steam heating,the quality of veneers sliced with real-time steam heating could be improved obviously,and the maximum reducing percentage of surface roughness perpendicular to and parallel to grain and back clearance were 11.55％,23.12％ and 28.06％,respectively.The surface roughness and the back clearance of veneers were both the smallest under steam heating after water-boiling.

Lignocellulosic butanol residue (BR), obtained as the by-product of lignocellulosic butanol production, was used for the preparation of lignin-based phenol-resorcinol-formaldehyde resins (LPRFRs) by condensation polymerization. The lignin was first phenolated under sodium hydroxide catalysis at 90 to 92 °C at various phenolation times (1.0 to 4.0 h). The structural differences between BR and phenolated BR (PBR) were studied using Fourier transform infrared (FT-IR) spectroscopy, ultraviolet (UV) spectroscopy, thermogravimetric analysis (TGA), and gel permeation chromatography (GPC). The BR phenolated for 3.0 h had high phenol hydroxyl content, low molecular weight, and good thermal stability. The LPRFRs with 30 wt.% BR had the lowest free formaldehyde and phenol. With the substitution of BR for phenol, the hydrophilicity of LPRFRs increased. In addition, the mechanical, fragility, thermal properties, and morphology of lignin-phenol-resorcinol-formaldehyde foams (LPRFFs) were also investigated. The LPRFFs had excellent comprehensive properties when 30 wt.% PBR was substituted for phenol. These experimental findings could provide a new avenue for further study and application of bio-phenol-resorcinol foams.