Renewable Biomass as a Platform for Preparing Green Chemistry

1 About the Special Issue Editor Qiaoguang Li is an associate professor and master’s supervisor in the Department of College of Chemistry and Chemical Engineering,Zhongkai University of Agriculture and Engineering.He received his PhD from Institute of Chemical Industry of Forestry Products,Chinese Academy of Forestry in 2018.He has been focusing his research on the chemical basis and application of natural resources.He has published nearly 30 international peer reviewed papers and applied for 10 patents.

Synergistic Modification of PVC with Nitrogen-Containing Heterocycle and Tung-Oil Based Derivative for Enhanced Heat Stabilization and Plasticization Behavior

The additives present in polyvinyl chloride(PVC)materials are the major source of organic by-products during PVC degradation.The thermal stabilizer and plasticizer are the main additives that endow PVC with the required properties during its processing.However,these two additives easily migrate when samples are obtained by physical mixing of the additives with PVC.This causes the reduction of PVC sample efficacy and the increase in the formation of organic by-products in the radiolysis process.In this work,two kinds of grafted PVC samples(tungoil derivative grafted PVC and Atz grafted PVC,abbreviated as P-GT4 and P-AZ3)were synthesized by chemical grafting of 3-amino-1,2,4-triazole(Atz)and tung-oil derivative on PVC,respectively.These two PVC samples were then blended at different mass ratios to obtain hybrid PVC materials with excellent plasticization,thermal stability and migration resistance ability.Differential scanning calorimetry(DSC),discoloration,Congo red test and thermogravimetric analysis(TGA)showed that when the mass ratio of P-GT4 to P-AZ3 in the mixed PVC resin was 1:3,the resulting P1:3-GT4-AZ3(P4)presented the best plasticization and thermal stability.The kinetics of thermal decomposition showed that the activation energy of P4 was much higher than that of the reference material[PVC/DOTP/CaSt2/ZnSt2,PVC/CZ41 for short]at mass lossα=20%and 80%.In addition,the leaching test showed that P4 material possessed excellent migration resistance ability.

Plasticizing Effect of Camellia oleifera Seed-Oil-Based Plasticizer on PVC Material Modification

In this study,as the plasticizer,Camellia oleifera seed-oil-based cyclohexyl ester(COSOCE)was prepared by the reaction of cyclohexene oxide and refined C.oleifera seed oil(RCOSO)obtained by acidification hydrolysis after saponification.In addition,the structure of the target product was confirmed by Fourier transform infrared(FTIR)spectroscopy,nuclear magnetic resonance(NMR)spectroscopy,and Raman spectroscopy.COSOCE was used as plasticizer-modified polyvinyl chloride(PVC)membranes.The structure of the COSOCE-modified PVC membranes were characterized by Raman spectroscopy and scanning electron microscopy(SEM).The properties of the COSOCE-modified PVC membrane were characterized by contact angle measurements,universal testing machine,thermogravimetric analysis(TGA),and differential scanning calorimetry(DSC).The results revealed that(1)The COSOCE-modified PVC membranes exhibit a good microscopic morphology.Combined with energy-dispersive X-ray spectroscopy(EDS)and contact angle measurement results,the COSOCE-modified PVC membranes are confirmed to be a hydrophilic material.(2)The modified PVC membrane with 60%COSOCE exhibited the best mechanical properties.The tensile strength reached 23.56±2.94 MPa.(3)COSOCE-modified PVC material exhibited better thermal stability,with a loss rate of less than 75%at the end of the first decomposition stage.Compared with that of the dioctyl-phthalate(DOP)-modified PVC membrane,the initial decomposition temperature of PVC was increased by 1.17°C–8.17°C,and the residual rate was increased by 0.67%–5.75%.The carbon–carbon double bond in the COSOCE molecular structure can remove the free radicals generated during the degradation of PVC material and slow down the decomposition rate of PVC.In addition,the double bond can be cross-linked partially with the PVC molecular chain containing the conjugated polyene structure,thereby increasing the movement resistance of the PVC molecular chain segment.Hence,COSOCE can replace DOP as a PVC plasticizer.

高性能生物基聚氯乙烯增塑剂的制备与应用

以来源广泛的废弃油脂地沟油为主要原料,通过酯交换、环氧化和开环等常用的化学反应制备出性能优良的聚氯乙烯(PVC)增塑剂。气相色谱-质谱联用(GC-MS)分析表明,相转移催化剂([(C_8H_(17))_3NCH_3]_3[PO_4[W(O)(O_2)_2]_4]^(3-))可以在无羧酸条件下有效地催化脂肪酸结构中双键发生环氧化反应;利用核磁共振氢谱、红外光谱对各种产物进行表征,结果表明目标产物AC-FAME-BA被成功制备。不同增塑剂增塑PVC制品的力学性能和动态力学热分析结果表明,添加AC-FAME-BA可以有效降低PVC制品的模量和玻璃化温度,增加断裂伸长率,50 phr的添加量可以使PVC材料的玻璃化转变温度降低到22.8℃;对比分析各制品的力学性能、动态力学热分析和耐挥发性能,结果表明ACFAME-BA的增塑性与相容性要优于环氧大豆油(ESO),与邻苯二甲酸二辛酯(DOP)相当。对比ESO和DOP,AC-FAMEBA(35 phr)增塑的PVC在极性溶剂(乙醇)中抽出量相对较多,在弱极性溶剂(石油醚)中抽出量相对较少。这些应用分析结果表明AC-FAME-BA是一种性能优良的PVC增塑剂,在某些领域可以完全替代DOP。

聚氨酯预聚体改性酚醛泡沫的研究进展

酚醛泡沫是近几年发展起来的一类新型泡沫塑料,具有阻燃、低烟、自熄等独特性能,传统酚醛泡沫是由酚醛树脂在固化剂、发泡剂、表面活性剂及其他助剂存在条件下,同时发泡、固化制成。固化后的酚醛树脂因自身结构的缺陷,从而使得制备的酚醛泡沫存在延伸率低、硬度大、耐冲击性差、粉碎率高等问题,限制了其产品应用及快速发展。因此对酚醛树脂及其泡沫进行改性研究以降低其脆性,提高其韧性,具有一定理论和现实意义。文中阐述了酚醛泡沫的增韧方法,着重介绍了直接混合法、NCO链端预聚体法以及OH链端预聚体法等3种聚氨酯预聚体增韧酚醛泡沫的方法,并分析了聚氨酯预聚体增韧酚醛泡沫的增韧机理。最后总结了聚氨酯预聚体改性酚醛泡沫存在的问题。

Vitrimer材料的制备及性能研究进展

Vitrimer材料是一种含动态交联网络的高分子聚合物,在高温条件下,快速的动态交换反应使网络的拓扑结构发生改变和重排,从而使材料具有黏弹性和"流动性";并在保持材料化学结构和性能完整的情况下具有可塑性和可再加工性能。文中重点从酯交换反应、转酰胺反应、二硫化物重排反应和烷基转移反应等可逆交换反应类型论述了近年来国内外Vitrimer材料最新研究进展,对材料的动态可逆机理及性能特征进行了分析和对比,并对未来研究发展趋势进行了展望。

Preparation and Characterization of Potassium Monopersulfate/Ethyl Cellulose Microcapsules and Their Sustained Release Performance

Environmental cleaning is an important aspect of bacteria control.Ethyl cellulose microcapsules containing potassium monopersulfate(PMCM)were prepared by emulsified solvent diffusion method.The chemical structure and microstructure of the obtained PMCM was characterized by methods of Fourier transform infrared spectroscopy(FT-IR),optical microscopy,scanning electron microscopy and X-ACT energy dispersive X-ray spectroscopy.The SEM micrographs of the PMCM containing 21.6%of C,46.8%of O,10.7%of S and 19.4%of K was relatively smooth.Thermal stability,sustained release performance,and antimicrobial activity of PMCM were investigated.The results showed that the drug loading and encapsulation efficiency of PMCM were 30.3%and 42.6%respectively.Potassium monopersulfate was fully released after 8 h,following a Fickian diffusion mechanism.Results showed that the microcapsules prepared with a high concentration of potassium monopersulfate solution showed a good antimicrobial effect.The microcapsule wall of the resulting PMCM increased with increasing ethyl cellulose content and had high thermal stability from the data of 69%residue rate.The excellent thermal stability and high sustained release performance of PMCM showed high application value.

Preparation and characterization of tung oil-based flame retardant polyols

Three kinds of tung oil-based structural flame retardants polyols(TOFPs) were prepared by new methods in this paper. First, tung oil was used to produce monoglyceride and diglyceride by transesterification with glycerol by sodium methoxide. The products after transesterification were epoxidized by peracetic acid which was in-situ generated from acetic acid and hydrogen peroxide in the presence of sulfuric acid catalyst. And then, TOFPs were prepared from epoxidized alcoholysis tung oil(EGTO) with 9, 10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide(DOPO), diethyl phosphate(DEP) and diethanolamine(DEA) by ring-opening reactions, respectively. GPC was used to evaluate the conversion rate, at optimum reaction conditions, selectivity for monoglyceride in transesterification. The influence of different parameters such as temperature, mole ratio or mass ratio on the conversion rate of transesterification and epoxidation were investigated. The molecular structures of TOFPs were characterized by FTIR and ~1HNMR. Finally, tung oil-based polyurethane foams(TOPUFs) were prepared by a one-shot process using TOFPs with polyisocyanate. The LOI values of TOPUFs whose content of DOPO-EGTO,DEP-EGTO and DEA-EGTO were 100 wt% can reach to 26.2%, 25.1%, and 24.4%, respectively.

The Effects of DOPO-g-ITA Modified Microcrystalline Cellulose on the Properites of Composite Phenolic Foams

In order to improve the comprehensive performance of phenolic foam,9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide(DOPO)was grafted with itaconic acid(ITA)(DOPO-g-ITA)to modify microcrystalline cellulose(MCC).DOPO-g-ITA modified MCC(DIMMCC)was used to prepare composite phenolic foam(DCPF).The structures of DIMMCC were verified by Fourier transform infrared spectroscopy(FT-IR).The microstructure and crystalline property were characterized by scanning electron microscope(SEM)and X-ray diffraction(XRD)respectively.Compared with MCC,the crystallinity of DIMMCC was dramatically decreased,but the diffraction peak positions were unchanged.Thermal stability was decreased,and T_(i)decreased by 45.0°C.The residual carbon(600°C)was increased by 22.34%.With the dosage of DIMMCC/PR increased,compared with PF,the mechanical properties and flame retardancy of DCPF were increased.Especially,the dosage of DIMMCC/PR was 10%,the comprehensive properties of DCPF was better than others.

Preparation and Characterization of Tung Oil Toughened Modified Phenolic Foams with Enhanced Mechanical Properties and Smoke Suppression

In this study,we prepared a series of tung oil phenolic foams(TPF)by a one-pot method.The FT-IR and 1H NMR spectra confirm the successful Friedel-Crafts grafting of phenol to the long-chain alkyl group in tung oil.Modified TPFs exhibit enhanced mechanical properties,including compressive and flexural strengths of up to 0.278±0.036 MPa and 0.450±0.017 MPa,respectively,which represent increases of 68.75%and 86.72%over those of pure phenolic foam(PF).SEM spectra reveal the TPF microstructure to have uniform hexagonal cell morphology,narrower cell size distribution,and smaller mean cell size,suggesting enhanced mechanical properties.The TPF total smoke release decreased by 74.23%,indicating that the long alkyl chain significantly improves smoke suppression of the combusting foam.However,due to the flammability of the alkyl chains,the TPF limiting oxygen index decreases with increasing tung oil content.Moreover,TPF exhibits reduced thermal stability and high-temperature charring rate,elevated peak and mean heat release rates,and higher total heat release compared with pure PF.Therefore,future research will focus on the use of tung oil modified flame retardant to provide more robust phenolic foams.

Synthesis and Characterization of DOPO-g-CNSL and Its Effect on the Properties of Phenolic Foams

In order to improve the mechanical properties without reducing its flame retardancy of phenolic foams(PFs),9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide(DOPO)was introduced in the structure of cashew nut shell liquid(CNSL)to improve its flame retardant,and the product of DOPO grafting CNSL(DOPO-g-CNSL)was obtained to modify phenolic resin,and to prepare DOPO-g-CNSL modified PFs(DCMPFs).The structures of DOPO-g-CNSL were verified by Fourier transform infrared spectroscopy(FT-IR)and nuclear magnetic resonance(1H-NMR).Compared with CNSL,thermal stability of DOPO-g-CNSL was decreased and Ti decreased by 3.53%,but the residual carbon(800°C)was increased by 35.05%.Compared with pure PF,the mechanical properties,toughness and flame retardancy of DCMPFs were increased when the ratio of DOPO-g-CNSL to phenol(DOPO-g-CNSL/P)was no more than 10%.With the dosage of DOPO-g-CNSL/P increased,Ti of DCMPFs was slightly increased,but the carbon residues(800°C)were almost unchanged.And the cell sizes of DCMPFs were basically the same as the pure PF.By comprehensive analysis,the suitable dosage of DOPO-g-CNSL/P was no more than 10%.

Recent Development of Cardanol Based Polymer Materials-A Review

Polymers from renewable resources are receiving tremendous attention due to the increasing concerns on the depletion of fossil oils and deteriorated environments.Cardanol,as an abundant and renewable chemical raw material,has been widely used for the production of renewable polymer materials via converting into various of chemical monomers with active functional groups.This comprehensive review deals with various aspects of cardanol as a starting material the preparing various polymer and polymer composites such as benzoxazine resins,phenolic resin,polyurethanes,epoxy resin,vinyl ester polymers,polyamide and cyanate ester resins.The assessment of the future prospects for the use of cardanol to synthesise novel and valuable renewable materials is presented.

Study on Toughening Phenolic Foams in Phosphorus-Containing Tung Oil-Based Derivatives

Phenolic foams(PFs)as thermal insulation material with outstanding flame retardancy are required to match society’s ever-expanding safety expectations;however,a trade-off exists between flame retardancy and toughness.Here,for the first time,we synthesized a novel reactive phosphorus-containing tung-oil-based derivative and used it to toughen PF,resulting in PFs with a combination of excellent mechanical properties and flame retardancy.Compared with pure PF,the modified PFs exhibit enhanced mechanical properties,with specific compressive and flexural strengths as high as 5.67 MPa and 12.46 MPa,which represent increases of 90.67%and 178.7%over those of pure PF,respectively.Meanwhile,the limiting oxygen index(LOI)values of the modified PFs are improved as much as 40.83%.Scanning electron microscopy micrographs show that the microstructure of the modified PFs is better than that of pure PF,with a more uniform cell morphology,a narrower pore size distribution range,and a smaller average pore size,all of which are beneficial to the foam’s mechanical properties.This study provides a scientific paradigm for the development of advanced PFs based on renewable biological resources.

Synthesis of Poly(acrylic acid)-Grafted Carboxymethyl Cellulose for Efficient Removal of Copper Ions

Biocompatible and high content grafted carboxymethyl cellulose-g-poly(acrylic acid)powder was successfully synthesized in an aqueous system,and used as adsorbents for the removal of Cu(II)in aqueous solution.The copolymer was characterized by FT-IR and SEM techniques.Graft copolymerization introduced a large number of carboxyl groups in the polymer and caused the micro-surface of the material to be porous.The fundamental adsorption behaviors of the material were studied.The adsorption kinetics was well fitted with pseudo-second order equation,while the adsorption isotherm preferred to be described the Langmuir equation.The maximum adsorption capacity obtained from the Langmuir model was 154.32 mg/g,indicating that the adsorption capacity of carboxymethyl cellulose was improved remarkably after grafting poly(acrylic acid).Moreover,Fourier transform infrared spectroscopy(FT-IR)has been used to investigate the adsorption mechanisms at molecular levels,which revealed that carboxyl groups are facile to form bidentate carboxylates with metal ions.Thus,this environment friendly copolymer will be a promising candidate for application in removal of heavy metal ions.

Synthesis of Bio-base Plasticizer Using Waste Cooking Oil and Its Performance Testing in Soft Poly(vinyl chloride)Films

Waste cooking oil was modified to prepare bio-base plasticizers(a,b and c)with terephthalic acid,adipic acid and benzoic acid by transesterification,epoxidation and ring opening reactions,respectively.The polyvinyl chloride(PVC)films(a/PVC,b/PVC and c/PVC)were prepared using a,b and c as bio-base plasticizers.The epoxidation and ring opening reactions were mainly investigated through GC-MS analysis.The structures of bio-base plasticizers(a,b and c)were confirmed by Fourier transform infrared spectroscopy(FT-IR),^(1)H NMR and ^(13)C NMR.The mechanical properties of a/PVC were as good as those of PVC films with the dioctyl phthalate(DOP)plasticizer.Meanwhile,the elongation at break of c/PVC reached 422%.The glass transition temperature(Tg)from dynamic mechanical analysis(DMA)was reduced to 30.6℃,45.3℃,23.6℃and 40.6℃,respectively when 40 phr of a,b,c and DOP plasticizer were added.Results of thermogravimetric analysis(TGA)illustrated that the thermal degradation stabilitiy of a/PVC films was better than those of c/PVC and DOP/PVC.The volatility losses of a,b and c were lower than that of the DOP.Bio-base plasticizers a and c exhibited excellent migration resistance in different solutions(distilled water,50%ethanol(w/w)).The FT-IR of PVC films showed that the downfield shifts of the—CH—Cl groups of the PVC plasticized with a and c were greater than that of b/PVC.The bio-base plasticizers b had a better plasticizing effect at low temperature.

Lignin-based phenolic resin modified with whisker silicon and its application

In this study,lignin-based phenolic resin was modified with whisker silicon and preparation of the phenolic foam was carried out.The resin and foam materials were characterized by Fourier transform infrared spectroscopy(FT-IR),thermo gravimetric analyzer(TGA),thermal conductiv-ity test,limit oxygen index(LOI)analyzer and cone calorimeter.The results showed that when the content of lignin and whisker silicon increased,the oxygen index of the foam increases and the calorific value of combustion decreased.However,if the amount of lignin increased,the open porosity of the foam and the thermal conductivity increased.When the lignin substitution rate was 30%and the whisker silicon addition amount was 1%,the phenolic foam(PF4)had the best performance:the 57.1%mass lost at 600℃ and the thermal stability was 16.8%higher than that of ordinary resin.The LOI was 49.6%,and 39.3%higher than that of ordinary phenolic foam.

Synthesis and Application of UV-curable Phosphorous-Containing Acrylated Epoxidized Soybean Oil-based Resins

A novel phosphorous-containing acrylated epoxidized soybean oil-based(P-AESO)resin was developed via the ring-opening reaction of epoxidized soybean oil(ESO)with diphenylphosphinic chloride(DPPC),followed by acrylation of the resulting groups.The chemical structure was characterized by Fourier transform infrared spectroscopy(FT-IR),and ^(1)H nuclear magnetic resonance(^(1)H NMR).Subsequently,the viscosity and volumetric shrinkage of the obtained P-AESO resins were studied.Then the oligomer was formulated into UV-curable coatings,and the mechanical,thermal,and coating properties of the resulting UV-cured bioresins were studied by tensile testing,dynamic mechanical thermal analysis(DMA),thermogravimetric analysis(TGA)coupled with FT-IR spectroscopy(TGA-FT-IR),hardness,adhesion,pencil hardness and chemical resistance.Furthermore,the UV-curing behavior of the P-AESO resin was determined by real-time realtime infrared(RT-IR).Meanwhile,compared with coating from acrylated epoxidized soybean oil(AESO),the P-AESO system coatings showed better volumetric shrinkage,excellent adhesion,and enhanced thermal and glass transition temperature(Tg)while maintaining reasonably final C=C conversions and cross-link density.For instance,the obtained P-AESO/trimethylolpropanetriacrylate(TMPTA)20 material possessed a volumetric shrinkage of 4.1%,Tg of 115.6℃,char yield of 9.47%,and final C=C conversions of 81.4%respectively,which exhibited superior values than that of the AESO/TMPTA20 material.The improvement of the P-AESO coating performances could contribute to the architectures that combined the structural features of phosphorous-containing rigid benzene.The developed P-AESO resin is promising for applications in the UV-curable coatings.