聚膦腈共混物的性能

介绍了聚膦腈共混物的热稳定性、阻燃性、气体渗透性、光导电性、尺寸稳定性和调控降解速度性能,并对其发展前景进行了展望。     

可生物降解聚膦腈的合成研究进展

在简要介绍可生物降解聚膦腈分类的基础上,综述了氨基取代、烃氧基取代、多官能团亲核试剂取代和侧链衍生化合成的单一取代聚膦腈的合成研究进展,总结了合成混合取代聚膦腈的目的和方法,简述了影响混合取代聚膦腈合成反应的因素和共混或共聚聚膦腈的合成研究概况。     

碱相转移催化脱水法合成肉桂腈的研究

研究了不同碱对肉桂醛肟的催化脱水效果及不同PTC的催化作用效果,并确定了使用KOH-TBAB催化脱水法合成肉桂腈的最佳反应条件。最佳反应条件为:TBAB的用量为6%(摩尔分数),KOH的用量为15%(摩尔分数),反应温度为124～126°C,反应时间为2.5h,在此条件下肉桂醛肟转化成肉桂腈的产率达90.3%。     

碱相转移催化脱水法合成柠檬腈的研究

研究了不同碱对柠檬肟的催化脱水效果及不同 PTC的催化作用效果 ,并用正交实验设计法确定了使用 KOH- TBAB催化脱水法合成柠檬腈的最佳反应条件。在此条件下 ,柠檬肟到柠檬腈产率达 91 .0 %。     

二丙烯酸酯参与的反应挤出制备长链支化PP

研究了二丙烯酸酯参与的反应挤出制备长链支化聚丙烯过程,重点考察了二丙烯酸酯双键间链段长度以及单体用量对长链支化程度的影响。结果表明,1,4-丁二醇二丙烯酸酯(BDDA)在聚丙烯分子链上具有较强接枝能力;在接枝率相当的情况下,悬垂双键参与偶合扩链的能力会随双键间链段长度增加而下降。单体接枝率增加以及悬垂双键反应能力增强均会使长链支化程度增大。随着二丙烯酸酯用量增加,长链支化程度增加;单体过量会使大分子自由基偶合扩链程度加重,导致局部交联形成凝胶。     

催化加氢制备对羟基苯甲脒

本实验采用Raney—Ni作为催化剂,研究了由对羟基苯腈合成对羟基苯甲脒的工艺条件。通过实验考察了时间（5h～11h）、压力（0．3MPa～0．8MPa）、温度（50℃～85℃）等因素对产率的影响。得到了适宜的工艺条件为：反应压力0．7MPa、反应时间9h、搅拌速率600r·min^-1、反应温度70℃。     

3,4-二羟基苯腈的合成

以3-甲氧基-4-羟基苯甲醛（香兰素）为原料,经与盐酸羟胺反应得到3甲氧基-4-羟基苯腈,再与碱金属卤化物经脱甲基化反应合成3,4-二羟基苯腈,产品含量99.8%,以香兰素计总收率75.2%。与其他合成方法比较,这条合成路线更适合于工业化。     

3,5-二羟基苯腈的合成

以3,5-二羟基苯甲酸为原料,乙酸酐、氨水、二氯亚砜作为试剂,经4步反应合成了3,5-二羟基苯腈,总收率66%。     

三乙烯二胺催化合成α-羟基膦酸二乙酯

本文报道了以亚磷酸二乙酯为原料,分别和6种芳香醛在三乙烯二胺(DABCO)的作用下发生Pudovik反应,合成6种芳基取代的α-羟基膦酸二乙酯的工艺。产物结构经¹H NMR和MS表征。并以2-溴-5-氟苯甲醛(2a)与亚磷酸二乙酯合成(2-溴-5-氟苯基)(羟甲基)膦酸二乙酯(1a)的反应为模型,考察影响产物收率的主要因素,确定最佳反应条件为：物料比为n₍(亚磷酸二乙酯))∶n₍(2-溴-5-氟苯甲醛))=1.2∶1;反应溶剂为四氢呋喃;室温反应2h。     

羟基亚乙基二膦酸四钠对二元驱油体系性能的影响

针对适用于孤东六区稠油冷采条件的无碱超低界面张力两亲聚合物强化泡沫驱油体系,通过电导率、界面张力及黏度等手段研究了羟基亚乙基二膦酸四钠(HEDP-Na4)对石油磺酸盐/两亲聚合物体系界面张力及黏度的影响。实验结果表明,HEDP-Na4一方面能够通过盐效应调节石油磺酸盐的亲水亲油平衡,促进石油磺酸盐在油/水界面上的吸附,另一方面能够鳌合溶液中的Ca2+和Mg2+,减小高价金属离子对石油磺酸盐和Ⅰ型两亲聚合物的影响,从而使得体系界面张力大幅降低和黏度小幅升高;并且HEDP-Na4对石油磺酸盐与Ⅰ型两亲聚合物之间的相互作用影响不大。     

原子转移自由基聚合合成支化聚丙烯腈

以二乙烯苯为支化单体,α-溴代异丁酸叔丁酯为引发剂,CuBr和2,2'-联吡啶为催化体系,利用本体和溶液原子转移自由基聚合合成了支化聚丙烯腈.采用核磁共振谱仪、凝胶渗透色谱仪和多角度激光光散射仪等测试了聚合物结构、相对分子质量及其分布.用无水乙酸钠对支化聚丙烯腈进行末端改性,得到了在硫氰酸钠水溶液中性能稳定、可长期保存的支化聚丙烯腈,而改性对聚合物的耐热性能没有影响.     

Semibatch RAFT polymerization for branched polyacrylamide production: Effect of divinyl monomer feeding policies

Star and hyperbranched polyacrylamides (s‐PAMs and b‐PAMs) were synthesized via semibatch RAFT copolymerization of acrylamide (AM) and N,N′‐methylenebisacrylamide (BisAM) using four monomer feeding policies. The BisAM to chain transfer agent (CTA) ratios from 1 to 40 at a constant [AM]₀/[CTA]₀ of 600 were investigated at 60°C. The s‐PAMs with the number of arms of 1.4–12.8 and 1.8–8.4 were, respectively, produced by arm‐first (AF) and core‐first (CF) approaches, whereas the b‐PAMs having the branching density of 1.34–13.1C/1000Cs were synthesized by constant BisAM feeding (semibatch polymerization, SB) and batch (batch polymerization, BA). Soluble b‐PAMs were produced with the four feeding policies at [BisAM]₀/[CTA]₀ of 5. However, when the [BisAM]₀/[CTA]₀ was increased to 30, the gelation occurred with the CF and BA approaches while the AF and SB synthesized soluble branched PAMs. The AF and SB approaches appeared to be practical in producing the respective s‐PAM and b‐PAM at high [BisAM]₀/[CTA]₀ ratios or low CTA usages. © 2012 American Institute of Chemical Engineers AIChE J, 59: 1322–1333, 2013     

Preparation and rheological investigation of tough PAAm hydrogel by adding branched polyethyleneimine

In this article, tough hydrogels are prepared by introducing the polyethyleneimine (PEI) with branched structure and a large number of  NH₂ and  NH groups into permanently crosslinked polyacrylamide (PAAm) hydrogels matrix. To investigate the effects of B-PEI and chemical crosslinking agent (Bis) on the strength and toughness of hydrogels, a series of B-PEI/PAAm hydrogels with different mass percentage of Bis and B-PEI were manufactured and the rheological and swelling properties were compared. For all hydrogels, the storage modulus (G′) was much higher than the loss modulus (G″) in the linear viscoelastic region through the whole frequency range. The solid-like behavior and elastic nature (G′ > G″) are attributed to the permanent covalence crosslinking. Therefore, G′ increased when more Bis was added. For the nonlinear oscillatory shear measurement, hydrogels with B-PEI broke at larger γ than the pure PAAm hydrogels, indicating that the toughness of B-PEI/PAAm hydrogels has been improved by introducing B-PEI. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48541.     

支化型苯乙烯-马来酸酐共聚物超细包覆碳黑的制备

采用相分离技术在炭黑表面包覆支化型苯乙烯-马来酸酐共聚物(BPSMA)制备超细包覆炭黑,探讨了相分离剂滴加速度、BPSMA用量、pH、炭黑质量分数以及分散时间对超细包覆炭黑粒径的影响。FTIR、TEM和对水接触角测试结果证实,炭黑表面包覆了BPSMA,超细包覆炭黑较佳的制备工艺为:相分离剂滴加速度3 mL/min,BPSMA用量为炭黑质量的20%,pH=10,炭黑质量分数为8%,超声波处理时间10 min。与线型苯乙烯-马来酸酐共聚物包覆炭黑分散体相比,相同条件下,BPSMA超细包覆炭黑分散体的粒径较小,稳定性较高,其印花织物的K/S值和摩擦牢度较高。     

Effect of molecular structure in branched polyethylene on adhesion properties with polypropylene

Adhesion properties between branched polyethylene (PE) and isotactic polypropylene (PP) were studied by a peel test and scanning electron microscopy. In this study, two types of branched PEs were used; one is a linear low density polyethylene (LLDPE) and the other is a high pressure low density polyethylene (LDPE). The adhesive strength of the LLDPE/PP is much higher than that of LDPE/PP. Furthermore, the formation of PE influxes between PP spherulites has a small effect on the adhesion. The dynamic viscoelastic measurements for the binary blends composed of branched PE and PP were also carried out to estimate the interfacial tension by using a rheological emulsion model proposed by Palierne. The interfacial tension is 1.0 mN for LLDPE/PP and 2.1 mN for LDPE/PP, suggesting that the interfacial thickness of LLDPE/PP is about twice that of LDPE/PP. The adhesive strength between branched PE and PP will be determined by the interfacial thickness, which represents the entanglements between two polymers. © 1998 John Wiley & Sons, Inc. J. Appl. Polym. Sci. 70: 457–463, 1998     

Study of mechanical and rheological behaviors of linear and branched polycarbonates blends

A study of the mechanical and rheological properties of linear and branched polycarbonates blends is presented. Phase separations of the blends were checked through DSC and SEM, and, subsequently, mechanical and rheological properties were investigated. Phase separations were not observed in the blends. The mechanical properties were examined through tensile, flexural, and impact tests. All the mechanical properties of the blends were relatively independent of the compositions. For study of the rheological properties, melt viscosity, storage and loss moduli, and melt tension of the blends with various compositions were examined at various temperatures. The dependence of the viscosity on the molecular weight was also studied. As the content of branched polycarbonate increases, the dependence of the viscosity on the molecular weight and the shear thinning behavior became more marked. Melt tensions were also increased as the branched polycarbonate content increased in the blends for all tested temperatures. In this study, the blend systems which have same mechanical properties but different rheological properties can be obtained through blending of linear and branched polycarbonates. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 1814–1824, 2001     

A novel strategy to branched polyacrylonitrile via one‐pot RAFT copolymerization of acrylonitrile and an asymmetrical divinyl monomer

Branched polyacrylonitriles were prepared via the one‐pot radical copolymerization of acrylonitirle and an asymmetric divinyl monomer (allyl methacrylate) that possesses both a higher reactive methacrylate and a lower reactive allyl. RAFT technique was used to keep a low‐propagation chain concentration via a fast reversible chain transfer euilibration and thus the cross‐linking was prevented until a high level of monomer conversions. This novel strategy was demonstrated to engenerate a branched architecture with abundant pendant functional vinyl and nitrile groups, and controlled molecular weight as a behavior of controlled/living radical polymerization characteristics. The effect of the various experimental parameters, including temperature, brancher to monomer molar ratio, and chain transfer agent to initiator molar ratio, on the control of moleculer dimension (molecular weight and polydispersity indices) and the degree of branching were investigated in detail. Moreover, ¹H NMR and gel permeation chromatography confirm the branched architecture of the resultant polymer. The intrinsic viscosity of the copolymer is also lower than the linear counterpart.© 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

无喷霜硫化体系中硫黄用量对三元乙丙橡胶/白炭黑硫化胶性能的影响

采用无喷霜硫黄硫化体系,考察了硫黄用量对三元乙丙橡胶(EPDM)/白炭黑(WCB)混炼胶硫化特性及硫化胶物理机械性能、耐热老化性能、动态力学性能和压缩永久变形的影响。结果表明,在硫黄用量为0.5~1.5份的条件下,随着硫黄用量的增加,EPDM/WCB混炼胶的硫化速率减慢,硫化胶的拉伸强度先升高后下降,当硫黄用量为1.00份时达到最大值(22.4 MPa),同时扯断伸长率和永久变形逐渐下降,邵尔A硬度升高;热空气老化后,硫化胶的拉伸强度、撕裂强度和硬度均提高,但扯断伸长率下降幅度较大;随着硫黄用量的增加,硫化胶的玻璃化转变温度向高温方向移动,损耗因子峰值先升高后下降,储能模量增大,压缩永久变形略有减小。     

Studies on the preparation of branched polymers from styrene and divinylbenzene

The self‐condensing vinyl polymerization of styrene and an inimer formed in situ by atom transfer radical addition from divinylbenzene and 2‐bromoisobutyl‐tert‐butyrate using atom transfer radical polymerization technique was studied. To study the polymerization mechanism and achieve high molecular weight polymer in a high polymer yield, the polymerization was carried out in bulk at 80°C. Proton nuclear magnetic resonance (¹H‐NMR) spectroscopy and gel permeation chromatography (GPC) coupled with multiangle laser light scattering (MALLS) were used to monitor the polymerization process and characterize the solid polymers. It is proved that the polymerization shows a “living” polymerization behavior and the crosslinking reaction has been restrained effectively due to the introduction of styrene. Polymers with high molecular weight (M_w.MALLS > 10⁵) can be prepared in high yield (near 80%). Comparison of the apparent molecular weights measured by GPC with the absolute values measured by MALLS indicates the existence of branched structures in the prepared polymers. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

RAFT polymerization and thiol-ene modification of 2-vinyloxyethyl methacrylate: Towards functional branched polymers

A vinyl functional polymer, viz, poly(vinyloxyethyl methacrylate) (poly(VEMA) was synthesized by the RAFT polymerization of an asymmetric divinyl monomer, VEMA. This polymer, with pendant vinyloxyl groups, was subsequently reacted with three thiol compounds; 2-mercaptoethanol, cysteamine and 3-mercaptoproponic acid via the thiol-ene reactions. The resulting branched polymers contained hydroxyl, amino and carboxylic acid functionalities suitable for further reactions and conjugations.