Hydrophobic cellulose fibers via ATRP and their performance in the removal of pyrene from water

In the present work, cellulose fibers were modified by grafting with poly(lauryl acrylate) and poly(octadecyl acrylate). The grafted materials were prepared by polymerization of the corresponding monomers via surface initiated atom transfer radical polymerization, starting from cellulose papers previously modified with 2‐bromoisobutyryl groups. The polymerizations were carried out in the presence of ethyl‐2‐bromoisobutyrate, as a sacrificial initiator, added to control the molecular weight of the anchored segments, and polymerization kinetics. The grafting of both polymers was confirmed by infrared spectroscopy and elemental analysis. The effect of grafting these polymers on the thermal stability, morphology, and surface properties of cellulose fibers was studied using thermogravimetric analysis, scanning electron microscopy, and measuring water contact angle, respectively. The results reveal that grafting poly(lauryl acrylate) and poly(octadecyl acrylate) to cellulose confers the filter paper a hydrophobic character, and increases its affinity with pyrene, allowing the removal of this pollutant from water. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 44482.     

Synthesis of controlled thermoresponsive PET track‐etched membranes by ATRP method

Controlled thermoresponsive PET track‐etched membranes were synthesized by grafting N‐isopropylacrylamide (NIPAAm) onto the membrane surface via atom transfer radical polymerization (ATRP). The initial measurements were made to determine the anchoring of ATRP initiator on PET membrane surface. Thereafter, polymerization was carried out to control the mass of polymer by controlling reaction time grafted from the membrane surface and, ATR‐FTIR, grafting degree measurements, water contact angle measurements, TGA, and SEM were used to characterize changes in the chemical functionality, surface and pore morphology of membranes as a result of modification. Water flux measurements were used to evaluate the thermoresponsive capacity of grafted membranes. The results show the grafted PET track‐etched membranes exhibit rapid and reversible response of permeability to environmental temperature, and its permeability could be controlled by controlling polymerization time using ATRP method. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011.     

ARGET ATRP法合成聚氯乙烯接枝丙烯酸丁酯共聚物

以不稳定氯含量高的聚氯乙烯（U-PVC）和氯乙烯-溴代异丁酸烯丙酯共聚物（PVC-co-ABrMP）为大分子引发剂,使用电子转移催化再生原子转移自由基聚合（ARGET ATRP）进行丙烯酸丁酯（BA）的溶液接枝共聚。在固定CuCl₂：三（2-吡啶甲基）胺：辛酸亚锡（摩尔比）时,当CuCl₂用量（相对于氯乙烯链节数）小于0.1%时,BA转化率随CuCl₂用量增加而明显增加;辛酸亚锡与CuCl₂摩尔比大于50时,辛酸亚锡用量对聚合速率的影响较小;相同催化体系用量下,采用PVC-co-ABrMP为引发剂,可获得更高的BA转化率。通过PVC-co-ABrMP酯基水解得到PBA支链,其分子量分布指数为1.29,符合“活性”自由基聚合的特征。接枝PBA对PVC有明显的内增塑效果,PBA摩尔分数为32.75%的PVC-g-BA的玻璃化温度为8.34℃。     

ATRP法合成两亲性聚乙二醇-聚丙烯酸叔丁酯嵌段共聚物

以mPEG-Br为大分子引发剂,CuBr/PMDETA为催化体系,采用原子转移自由基聚合法(ATRP)合成了两亲性嵌段共聚物聚乙二醇-聚丙烯酸叔丁酯(mPEG-b-PtBA),并采用FT-IR,1H-NMR和GPC等表征了聚合物的结构.考察了单体与引发剂的配比、反应时间、反应温度及催化剂与配体的比例等因素对产物的分子量...     

Synthesis and characterization of functional gradient copolymers of glycidyl methacrylate and butyl acrylate

Epoxy-functional spontaneous gradient copolymers of glycidyl methacrylate (G) and n-butyl acrylate (B) were synthesized via atom transfer radical polymerization (ATRP). The copolymerization reactions were carried out in toluene solution at 70 °C, using methyl 2-bromopropionate (MBrP) as initiator and copper chloride with N,N,N′,N′′,N′′-pentamethyldiethylenetriamine (PMDETA) as the catalyst system. The kinetic behaviour of the statistical copolymerizations was studied in a wide composition interval with molar fractions of G ranging from 0.10 to 0.75. The synthesized copolymers were characterized by size exclusion chromatography (SEC) and nuclear magnetic resonance (NMR) spectroscopy. ¹H NMR was employed to determine the copolymer composition, demonstrating the gradient character of the copolymers along the main chain in the whole monomer conversion interval. Apart from this, the sequence distribution and stereoregularity were analyzed. These microstructural experimental data agreed well with those calculated from Mayo-Lewis terminal model (MLTM) and a Bernoullian statistic with an isotacticity parameter of σ_G = 0.28 and a coisotacticity parameter of σ = 0.30.     

Synthesis,characterization, and property of end-functionalized telechelic PST via ATRP

Polystyrene incorporating carboxylate group as α-end was synthesized by using initiator 4-chloromethyl benzoic acid via atom transfer radical polymerization. Its ω-chlorine end-group was transformed by cumic acid, diethyl malonate, and thiol, respectively, to form end-functionalized telechelic polystyrenes. These PSts with different functionalized ω-end group (PSt 1 , PSt 2 , and PSt 3) were obtained and characterized by H NMR and TGA. This type of end-functionalized telechelic polymers can further act as polymeric ligands to form polymeric metal complexes. In this study, PSt 1 with carboxylate group at each end was allowed to react with Eu(DBM)₂Cl·2H₂O to afford a new polymeric complex PSt 1 -Eu(III) showing significant red-light emission. Moreover, the film of PSt 1 -Eu shows similar emission pattern with its DMF solution. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

PVC／OMMT／WF纳米复合材料性能研究

对蒙脱土进行有机改性制得有机蒙脱土（OMMT），并制备了聚氯乙烯侑机蒙脱土／木粉（PVC／OMMT／WF）纳米复合材料。采用硅烷偶联剂对木粉表面进行改性，有效提高了聚氯乙烯／木粉（PVC／WF）复合材料的力学性能，其中加入1．5％（质量含量，下同）硅烷偶联剂可使复合材料的冲击强度和拉伸强度分别提高14．8％和18．5％。研究了OMMT的加入对木粉改性前后的PVC／WF复合材料力学性能、耐热性能及阻燃性能的影响，结果表明，木粉未经改性时，OMMT加入无助于PVC／OMMT／WF复合材料力学性能的提高；木粉用硅烷偶联剂改性后，添加少量的OMMT，可使PVC／OMMT／WF复合材料的冲击强度和拉伸强度明显提高。研究表明，添加OMMT可显著延迟复合材料的点燃时间，燃烧残余率也明显增加，OMMT是PVC／WF复合材料的高效阻燃剂。     

Synthesis and properties of a poly(sodium acrylate) bioadhesive nanocomposite

Poly(sodium acrylate) (PNaA) based nanocomposites were synthesized using different nanosilver loadings via redox solution polymerization at room temperature and under full exposure to the atmosphere. The nanocomposites exhibited increasing antibacterial activity with increased nanosilver content. Biocompatibility was determined using an MTT assay; no significant cytotoxicity was observed at the examined nanosilver loadings. Adhesion was measured using a tensile test and the stress versus strain curve showed an acceptable stress development in the model tissue using bioadhesive containing 2 wt% nanosilver. Introducing a second, more degradable polymer to the system as an interpenetrating polymer network enabled tuning the bioadhesive degradation rate.     

Poly(?-caprolactone)-block-polystyrene metallopolymers via sequential ROP and ATRP condition with in situ generated ruthenium catalyst

Poly(?-caprolactone)-b-polystyrene with vacant bipyridine coordinating sites and metallated AB type diblock with well-defined metal loci in the polymer chain were synthesized and characterized. Solution atom transfer radical polymerization (ATRP) of styrene where a poly(?-caprolactone) macromonomer acted as initiator and derivative complex of [Ru(p-cymene)Cl₂]₂ as catalyst is reported. ATRP reaction conditions with respect to polymer molecular weights and polydispersity indices (PDI) of the target bifunctional polymers were examined. Electronic absorption and emission spectra of the resultant functional polymers provided evidence of the ruthenium metal chromophores in the diblock copolymer. The thermal properties of all polymers were investigated by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA), and indicated that they possess a high thermal stability and are miscible in the molten state. The semicrystalline nature of the PCL macroligand and the morphology of thin films of the metal free diblocks were also elucidated by combination of atomic force microscopy (AFM), scanning electron microscopy (SEM) and wide angle X-ray diffraction (WAXD) studies.     

Synthesis and characterization of side-chain liquid-crystalline block-copolymers containing laterally attached photoluminescent quinquephenyl units via ATRP

A series of novel side-chain liquid-crystalline polymers (SCLCPs) consisting of laterally attached photoluminescent p-quinquephenyl (QQP) pendants with different flexible terminal- and/or side-alkoxy chains were synthesized via atom transfer radical polymerization (ATRP). Homopolymers (HP1-HP3) and block-copolymers (PSP1-PSP3 and PEOP1-PEOP3), where QQP units were copolymerized with styrene or ethylene oxide monomers, possessed the number average molecular weights (M_n) of 8.7-26.0 × 10³ with narrow PDI values of 1.08-1.26. Various characterization techniques of polarized optical microscopy (POM), differential scanning calorimetry (DSC), and X-ray diffraction (XRD) were used to investigate their mesomorphic properties, and all homopolymers and block-copolymers exhibited the nematic phase affected by the flexible terminal- and/or side-alkoxy chains of the conjugated rod-like pendants. In addition, the photophysical properties of these polymers were measured by UV-vis and photoluminescence (PL) spectroscopies, which showed blue PL emissions with rather high fluorescence quantum yields in solutions.     

Thermal degradation of polyesters filled with magnesium dihydroxide and magnesium oxide

Magnesium dihydroxide (MDH) was evaluated as char promoter into different polymers exhibiting various chemical structures. Char promotion was characterized using thermogravimetric analysis and pyrolysis‐combustion flow calorimetry. Gases released during pyrolysis were identified using pyrolysis coupled gas chromatography/mass spectrometry and thermogravimetric analysis coupled Fourier transform infrared spectroscopy. Relationships between the MDH effect (according to the char content and its thermal stability) and the chemical structure of the host polymers were identified. It was shown that MDH can be a good char promoter for aromatic polyesters such as polybutylene terephtalate and polyethylene terephtalate. Char promotion can be considered as one of the main mode‐of‐action of MDH at low or moderate filler content. An optimum was observed at approximately 20wt.% of MDH. Magnesium oxide was also studied as substitute to MDH to avoid hydrolysis phenomena due to the water release. But it was demonstrated that MDH was more efficient as a char promoter for polybutylene terephtalate than magnesium oxide. Copyright © 2015 John Wiley & Sons, Ltd.     

Synthesis of well‐defined glycoconjugate polyacrylamides via preactivated polymers prepared by ATRP

Poly(N‐acryloxysuccinimide) (polyNAS) with narrow molecular weight distributions (MWD) applicable for the preparation of well‐defined glycoconjugate polyacrylamides were successfully prepared by atom transfer radical polymerization (ATRP). The structures of polyNAS were characterized by ¹H‐NMR and GPC. GPC results showed that the molecular weight polydispersity indices (PDI) range from 1.17 to 1.29. The molecular weights could be calculated based on ¹H‐NMR results but GPC results of polyNAS by using 0.01M LiBr/DMF did not give accurate molecular weights, probably because of the complex interaction in the system. The effects of free N‐hydroxysuccimide produced in the polymerization processes on the free‐radical concentrations and apparent initiation efficiencies of ATRP were discussed. Well‐defined glycoconjugate polyacrylamides (i.e., with narrow molecular weight distributions and designed glycoconjugate degrees) were prepared by substituting N‐oxysuccimide units with galactosamine followed by reaction of ethanolamine. The galactose conjugate degrees were determined by ¹H‐NMR and the total substitutions of N‐oxysuccimides were verified by ¹H‐NMR and FTIR. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 189–194, 2005     

Synthesis and characterization of AB‐type copolymers poly(L‐lactide)‐block‐poly(methyl methacrylate) via a convenient route combining ROP and ATRP from a dual initiator

Diblock copolymers of poly(L ‐lactide)‐block‐poly(methyl methacrylate) (PLLA‐b‐PMMA) were synthesized through a sequential two‐step strategy, which combines ring‐opening polymerization (ROP) and atom transfer radical polymerization (ATRP), using a bifunctional initiator, 2,2,2‐trichloroethanol. The trichloro‐terminated poly(L ‐lactide) (PLLA‐Cl) with high molecular weight (M_n,GPC = 1–12 × 10⁴ g/mol) was presynthesized through bulk ROP of L ‐lactide (L ‐LA), initiated by the hydroxyl group of the double‐headed initiator, with tin(II) octoate (Sn(Oct)₂) as catalyst. The second segment of the block copolymer was synthesized by the ATRP of methyl methacrylate (MMA), with PLLA‐Cl as macroinitiator and CuCl/N,N,N′,N″,N″‐pentamethyldiethylenetriamine (PMDETA) as catalyst, and dimethyl sulfoxide (DMSO) was chosen as reaction medium due to the poor solubility of the macroinitiator in conventional solvents at the reaction temperature. The trichloroethoxyl terminal group of the macroinitiator was confirmed by Fourier transform infrared spectroscopy (FTIR) and ¹H‐NMR spectroscopy. The comprehensive results from GPC, FTIR, ¹H‐NMR analysis indicate that diblock copolymers PLLA‐b‐PMMA (M_n,GPC = 5–13 × 10⁴ g/mol) with desired molecular composition were obtained by changing the molar ratio of monomer/initiator. DSC, XRD, and TG analyses establish that the crystallization of copolymers is inhibited with the introduction of PMMA segment, which will be beneficial to ameliorating the brittleness, and furthermore, to improving the thermal performance. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Surface coated iron particles via atom transfer radical polymerization for thermal–oxidatively stable high viscosity magnetorheological fluid

A surface grafting technique for poly(2‐fluorostyrene) onto iron particles via atom transfer radical polymerization (ATRP) is described. Grafted poly(2‐fluorostyrene)–iron particles were synthesized by immobilizing 2‐4(‐chlorosulfonylphenyl)‐ethyltrichlorosilane to the iron particles through the covalent bond of a silanol group, followed by the polymerization of 2‐fluorostyrene monomer. The grafted polymer–iron particles display a higher thermal transition temperature compared to bulk polymer because the covalent bond between the polymer backbone and the surface of the iron particles restricts the molecular mobility. The molecular weight of the synthesized poly(2‐fluorostyrene) has been measured and it has a narrow molecular weight distribution (M_w/M_n < 1.1). From thermogravimetric analysis, the thermal stability of poly(2‐fluorostyrene) is superior to polystyrene. Also, the high viscosity magnetorheological fluid (HVMRF) prepared from surface coated iron particles has excellent thermo–oxidative stability, having nearly constant viscosity. These materials exhibit a large increase in shear yield stress for the off‐ and on‐state as compared to a benchmark high viscosity magnetorheological fluid (HVMRF) and ‐coated iron particle HVMRF. In addition, this type of fluid eliminates iron particle settling which is a common problem found in traditional magnetorheological fluids (MRFs). © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

悬浮聚合聚甲基丙烯酸甲酯／蒙脱土纳米复合材料的制备及表征

采用悬浮聚合法制备了聚甲基丙烯酸甲酯／蒙脱土（PMMA/MMT）纳米复合材料，利用X射线衍射仪、透射电子显微镜和傅里叶变换红外光谱等手段表征了复合材料的结构，研究了不同改性剂对复合材料结构的影响。通过热重分析考察了复合材料的热性能。结果表明，通过悬浮聚合可以成功制备剥离型纳米复合材料，PMMA基体与MMT可以产生较强的相互作用。MMT的加入可以显著提高复合材料的热稳定性。当MMT含量为10％（质量分数，下同）时，PMMA的最大分解温度提高了15℃。     

聚丙烯酸类超强吸水剂的合成与性能研究

以丙烯酸烯丙酯作为交联剂、丙烯酸(AA)为单体、过硫酸钾(KPS)为引发剂,采用溶液聚合法合成了一种聚丙烯酸类超强吸水剂。研究了合成条件对吸水性能的影响:当ρ(丙烯酸烯丙酯)=0 594g/L,ρ(KPS)=0 178g/L,单体中和度x(丙烯酸钠)=90%,c(丙烯酸钠)=4 17mol/L,聚合温度为60℃时,制得的聚合物每克吸去离子水最高达到1360mL,吸盐水(生理盐水)162mL。所得的聚合物具有良好的吸水可逆性,30min的吸水量可以达到饱和吸水量的90%。制得聚合物的热重分析表明,未吸水的该聚合物在350℃开始分解。聚合物吸水前后XRD测试结果显示:吸水前聚合物结构基本无规整性,吸水后膨胀使主链展开,结构趋于规整。     

Synthesis and properties of novel macromolecular coupling agents prepared by ATRP

Novel block and graft macromolecular coupling agents with well‐defined structures have been synthesized successfully by atom transfer radical polymerization (ATRP). The molecular weights and molecular weight distributions of those functional copolymers can be controlled because of the living/controlled ATRP. The structures and composition of block and graft copolymers with the monomers of butyl acrylate (BA), styrene (St), and 3‐methacryloxyl‐propyltrimethoxyl silicon (KH‐570) have been characterized by mean of ¹H NMR, IR, GPC, and UV. Because the KH‐570 of macromolecular coupling agents owns strong affinity to surface hydroxyl of fillers, inorganic fillers that were treated by the macromolecular coupling agents possess some new properties, for example increasing the effect between matrix and fillers of composites. The mechanical properties and morphology of composites with macromolecular coupling agents have been investigated by the dynamic mechanical spectra and SEM. The results showed that the damping value and compatibility of composites with macromolecular coupling agents were improved greatly when compared with that of composite with small molecular coupling agent. Furthermore with different contents of BA, St, and KH‐570 in the macromolecular coupling agents, the damping value of the composites are different. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 3919–3926, 2006     

载铜蒙脱土对聚氯乙烯材料阻燃性能的研究

通过离子交换反应将铜离子负载在无机层状蒙脱土上,采用十六烷基三甲基溴化铵对载铜蒙脱土进行有机改性,并将其作为阻燃剂添加到软质聚氯乙烯(PVC)材料中。利用X射线衍射对PVC/有机改性载铜蒙脱土的结构进行表征。结果表明,PVC分子链插层进入有机改性载铜蒙脱土层间形成插层型结构,且蒙脱土的层间距达到3.69 nm。热重分析、极限氧指数、垂直燃烧和烟密度测试结果表明,有机改性载铜蒙脱土有效改善了PVC的热稳定性,大幅提高了其阻燃性能。载铜蒙脱土的用量仅为PVC用量的3 %时,垂直燃烧即可达到V0级。     

稀土镧水滑石纳米复合材料的制备与表征

通过原位聚合法制备聚(甲基丙烯酸甲酯-丙烯酸丁酯)/Mg-Al-La水滑石(PMBA/Mg-Al-La-LDHs)纳米复合材料,以同样方法合成PMBA/Mg-Al-LDHs纳米复合材料为作为对照,经XRD表征与TEM测试表明,两种复合材料中LDHs是以剥离的形式分散在基体中,TG谱图揭示LDHs纳米层板可有效提高PMBA/LDHs纳米复合材料的热稳定性,将这两种复合材料以2%质量分数的添加量分别加到聚苯乙烯(PS)中,发现它们都能提高PS的力学性能,添加复合材料的PS拉伸强度比纯PS提高了100%。