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Photo-grafting Poly(acrylic acid) onto Poly(lactic acid) Chains in Solution

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Chinese Journal of Polymer Science 2020年第2期38卷 137-142,I0005页

作者： Jia-Xing wang Yan-Bin Huang wan-tai yang Department of Chemical Engineering Tsinghua University

Poly(lactic acid)(PLA)is one of the most important bio-plastics,and chemical modification of the already-polymerized poly(lactic acid)chains may enable optimization of its material properties and expand its application *** this study,we demonstrated that poly(lactic acid)can be readily dissolved in acrylic acid at room temperature,and acrylic acid can be graft-polymerized onto poly(lactic acid)chains in solution with the help of photoinitiator benzophenone under 254 nm ultraviolet(UV)*** photo-grafting polymerization of acrylic acid(PAA)has only been studied before in the surface modification of polymer *** graft ratio could be controlled by various reaction parameters,including irradiation time,benzophenone content,and monomer/polymer *** photo-grafting reaction resulted in high graft ratio(graft ratio PAA/PLA up to 180%)without formation of homopolymers of acrylic *** the PAA/PLA graft ratio was higher than 100%,the resulting PLA-g-PAA polymer was found dispersible in *** pros and cons of the photo-grafting reaction were also discussed.

关键词： Photo-grafting Polymer modification Poly(acrylic acid) Poly(lactic acid)

Synthesis and characterization of novel multifunctional epoxy resin

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Chinese Chemical Letters 2007年第4期18卷 469-472页

作者： Jue Cheng Jing Chen wan tai yang Key Laboratory of Science and Technology of Controllable Chemical Reactions Ministry of Education Beijing 100029 China College of Materials Science and Engineering Beijing University of Chemical Technology Beijing 100029 China

A novel multifunctional epoxy resin was synthesized by polyphenol and epichlorohydrin. The structure and molecular weight of the multifunctional epoxy were characterized by FTIR and ESI-MS. DSC and DMTA were used to investigate the thermal property of multifunctional epoxy cured by DDS. The thermal resistance of the synthesized multifunctional epoxy was much better than a standard diglycidyl ether of bisphenol-A epoxy.

关键词： Synthesis Polyphenol Multifunctional epoxy Thermal resistance

Surface Grafting of Phenolic Resole onto LDPE Films

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Chinese Chemical Letters 2006年第8期17卷 1133-1136页

作者： Jue CHENG Yi ZHENG wan tai yang Key Laboratory of Science and Technology of Controllable Chemical Reactions Ministry of Education Beijing 100029 College of Materials Science and Engineering Beijing University of Chemical Technology Beijing 100029

Low density polyethylene film surface-grafted phenolic resole was prepared by a sequential processes. Firstly, acrylic acid was grafted to the surface of low density polyethylene by photo-grafting. Secondly, the carboxylic groups in poly（acrylic acid） chains were transferred to sulfonic groups by the reaction of carboxylic groups with sulfanilic acid. Finally, a thin layer of phenolic resole was cured onto the surface of low density polyethylene. The grafting process was characterized by FTIR-ATR and gravimetric analysis. A possible model was proposed to interpret the experimental results.

关键词： Surface grafting low density polyethylene film sulfanilic acid phenolic resole.

“SERGEANTS AND SOLDIERS RULE” IN HELICAL SUBSTITUTED- ACETYLENE COPOLYMER EMULSIONS

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Chinese Journal of Polymer Science 2013年第1期31卷 179-186页

作者： Xuan Liu Ci Song Xiao-feng Luo wan-tai yang 邓建平 State Key Laboratory of Chemical Resource Engineering College of Materials Science and EngineeringBeijing University of Chemical Technology

The ＂sergeants and soldiers rule＂ occurring in helical copolymer emulsions derived from an achiral monomer （M1） and a chiral monomer （M2） was observed. TEM, GPC, and 1H-NMR techniques in combination demonstrate the formation of nanoparticles constituted by the copolymers. CD and UV-Vis spectra show the （co）polymer chains in the nanoparticles adopt helical structures of a predominant helicity, and the copolymers follow the ＂sergeants and soldiers rule＂ in forming helical structure.

关键词： Sergeants and soldiers rule Helical polymer Emulsion.

A facile method to prepare polypropylene/poly(butyl acrylate)alloy via water–solid phase suspension grafting polymerization

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Chinese Chemical Letters 2015年第11期26卷 1351-1354页

作者： Zhuo Li Li wang Yu-Hong Ma wan-tai yang The State Key Laboratory of Chemical Resources Engineering Beijing University of Chemical Technology Key Laboratory of Carbon Fiber and Functional Polymers Ministry of Education Beijing University of Chemical Technology

Polypropylene/poly（butyl acrylate） alloy is produced by water-solid phase suspension grafting polymerization with a submicrometer microdomain where graft polymerization occurs within micropores of polypropylene particles prepared by reactor granule technology （RGT）. The results show that the grafting percentage （GP） of butyl acrylate （BA） increases with the increase of the monomer concentration, which could reach 32.6% while the grafting efficiency （GE） is up to 98%. The addition of the crosslinking agent, triethylene glycol diacrylate （TEGDA）, could improve GP up to 36.3%. Transmission electron microscopic （TEM） micrographs demonstrate that PBA microdomains distributed in PP matrix increase in size less than 500 rim. Moreover, TEM images show that the grafting phase exhibits a singlephase behavior with the addition of TEGDA, which implies that the ratio of graft copolymer increased.

关键词： GraftingRadical polymerizationPorous materialsCrosslinking

Conventional Radical and RAFT Alternating Copolymerizations of Hydroxyalkyl Vinyl Ethers and Dialkyl Maleates

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Chinese Journal of Polymer Science 2023年第12期41卷 1856-1867,I0006页

作者： Yan-Xin Zhang Dong Chen Gao-Fei Hu Yu-Hong Ma wan-tai yang Beijing Engineering Research Center of Syntheses and Applications of Waterborne Polymers College of Materials Science and Engineering Beijing University of Chemical TechnologyBeijing 100029China Analytical and Testing Center Beijing University of Chemical TechnologyBeijing 100029China

The alternating copolymerization of hydroxyalkyl vinyl ethers and dialkyl maleates is investigated by conventional radical polymerization and reversible addition-fragmentation chain transfer polymerization(RAFT).The influence of comonomer structure,comonomer feeding ratios,and monomer concentrations on the copolymerization and the copolymer structure have been investigated *** 2-hydroxyethyl vinyl ether(HEVE)and dimethyl maleates(DMM)as comonomers,a well-defined alternating copolymer is prepared with M_(n)=3400 and M_(w)/M_(n)=1.93 up to 71.6% *** alternating sequential chain structure of the copolymers has been proved by both NMR and matrixassisted laser desorption/ionization time-of-flight mass spectrometry(MALDI-TOF MS).The experimental reactivity ratios and theoretical calculated highest occupied molecular orbital and the lowest unoccupied molecular orbital of vinyl ethers and alkyl maleates support that these monomer pairs have tendency to form alternating *** 2-cyanopropan-2-yl N-methyl-N-(pyridin-4-yl)carbamodithioate as the RAFT agent,the molecular weight of HEVE and DMM copolymer increases with the monomer conversion,demonstrating a controlled radical polymerization feature with well-controlled molecular weight and relatively narrower molecular weight *** alternating copolymer of HEVE and DMM as macro-CTA(M_(n)=5200 and M_(w)/M_(n)=1.46),both the chain extension with HEVE and DMM(M_(n)=10400 and M_(w)/M_(n)=1.72)and block copolymerization with vinyl acetate have been successfully achieved(M_(n)=8500 and M_(w)/M_(n)=1.52).

关键词： Radical polymerization Vinyl ethers Maleates Alternating copolymer RAFT polymerization

Synthetic Features and Mechanism for the Preparation of Vinyl Chloride-co-Butyl Acrylate-co-Vinyl Acetate Terpolymer via Precipitation Polymerization

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Chinese Journal of Polymer Science 2023年第11期41卷 1714-1724,I0006页

作者： Chang-Tong Song Xian-Hong Zhang Dong Chen Yu-Hong Ma wan-tai yang State Key Laboratory of Chemical Resource Engineering Beijing University of Chemical TechnologyBeijing 100029China College of Material Science and Engineering Beijing University of Chemical TechnologyBeijing 100029China

Without any type of su rfactant or dispersing agent,precipitation polymerization has great superiorities in both polymer synthesis and *** the present work,the polymerization of vinyl chloride(VC),n-butyl acrylate(BA),and vinyl acetate(VAc)are conducted in the precipitation polymerization system and series of their random terpolymers poly(vinyl chloride-co-n-butyl acrylate-co-vinyl acetate)(PCBV)are synthesized *** effects of various polymerization conditions,including solvent polarity,temperature,initiator concentration,and monomer feed ratios on the polymerization kinetics,number-average molecular weight(M_(n)),and terpolymer composition are investigated *** solvent and the monomer feed ratio are crucial factors not only for the polymer morphology,but also for the reaction *** the non-polar solvent such as n-hexane,the PCBV displays particle morphology when the composition of BA ratio lower than 10 wt%.Otherwise,the PCBV forms a uniform polymer phase and precipitates out from the *** the polar solvent,e.g.,dimethyl carbonate(DMC)and ethanol,the PCBV polymer maintains a slurry state either in low or in high monomer feed ***,VC based ternary copolymer that obtained in n-hexane has much lower M_(n)(40 wt%)compared with emulsion and suspension ***,the terpolymer can be easily sepa rated by simple centrifugation.

关键词： Precipitation polymerization Copolymerization Vinyl chloride Low molecular weight

AMPHIPHILIC STAR-BLOCK COPOLYMERS BY IODIDE-MEDIATED RADICAL POLYMERIZATION

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Chinese Journal of Polymer Science 2007年第6期25卷 609-619页

作者： Bing-yi Li Yan Shi Zhi-feng Fu wan-tai yang Shu-ke Jiao State Key Laboratory of Chemical Resource Engineering Beijing University of Chemical Technology Beijing 100029 China

Amphiphilic star-block copolymers composed of polystyrene and poly（acrylic acid） were synthesized by iodide- mediated radical polymerization. Firstly, free radical polymerization of styrene was carried out with AIBN as initiator and 1,1,1-trimethyolpropane tri（2-iodoisobutyrate） as chain transfer agent, giving iodine atom ended star-shaped polystyrene with three arm chains, R（polystyrene）3. Secondly, tert-butyl acrylate was polymerization using polystyrene obtained as macro-chain transfer agent, and star-block copolymer, R（polystyrene-b-poly（tert-butyl acrylate））3 with controlled molecular weight was obtained. Finally, amphiphilic star-block copolymer, R（polystyrene-b-poly（acrylic acid））3 was obtained by hydrolysis of R（polystyrene-b-poly（tert-butyl acrylate））3 under acidic condition.

关键词： Living radical polymerization Iodide-Mediated radical polymerization Star-block copolymers Amphiphilic copolymers.

SYNTHESIS AND CHARACTERIZATION OF BIODEGRADABLE POLYESTERAMIDES CONSTRUCTED MAINLY BY ALTERNATING DIESTERDIAMIDE UNITS FROM N,N'-BIS(2-HYDROXYETHYL)-ADIPAMIDE AND DIACIDS

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Chinese Journal of Polymer Science 2013年第3期31卷 452-461页

作者： Hui-yun Sun Tiao Yin 赵京波 Zhi-yuan Zhang wan-tai yang Key Laboratory of Carbon Fiber and Functional Polymers Ministry of Education State Key Laboratory of Chemical Resource Engineering College of Materials Science and EngineeringBeijing University of Chemical Technology

Two kinds of aliphatic alternating polyesteramide prepolymers were prepared through melt polycondensation from N,N＇-bis（2-hydroxyethyl）-adipamide and adipic acid or sebacic acid. Chain extension of them was conducted with 2,2＇-（1,4- phenylene）-bis（2-oxazoline） and adipoyl biscaprolactamate as combined chain extenders. The chain extended polyesteramides （ExtPEAs） were characterized by IR, 1H-NMR, differential scanning calorimetry, thermogravimetric analysis, wide angle X-ray scattering, tensile test and enzymatic degradation. The results showed that the ExtPEA（4,m）s were mainly constituted with the diester adipamide alternating units. ExtPEA（4,4） and ExtPEA（4,8） had Tm of 83.8℃ and 85.8℃ and initial decomposition temperature above 310.0℃. They crystallized similarly as Nylon-66 did and were flexible thermoplastic materials with tensile strength up to 25.64 MPa and strain at break up to 737%.

关键词： Alternating polyesteramides Polycondensation Chain extension Diamidediol Properties.