Nanocomposites of vinyl chloride–acrylonitrile copolymer and silica

Vinyl chloride–acrylonitrile (VC–AN) copolymer was synthesized through emulsion copolymerization. VC–AN copolymer/silica nanocomposites were prepared by solution blending of copolymer and silica in a common solvent, N,N‐dimethylformamide (DMF). The rheology studies show that the shear‐thinning behavior of the VC–AN copolymer solution becomes less distinct as nano particles are introduced. It was also found that the viscosity of the copolymer solution decreases with adding small amount of nano particles. Transmission electron microscopy observations indicate that the UV‐treated silica could disperse well in the copolymer matrix. Differential scanning calorimeter studies suggest that the presence of the silica suppresses crystallization of the AN segments in the copolymers. Because of the interactions between copolymer chains and inorganic particles, the thermal stability and mechanical strength of the VC–AN copolymers are improved considerably. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 43: 3127–3134, 2005     

Synthesis and Structure of 1—Cyclopentylindenyl Lanthanide（Ⅱ）Complexes and Their Catalytic Behavior for Polymerization of Acrylonitrile

The reaction between K(1‐C₅H₉C₉H₆) and anhydrous LnCl₃ (Ln=Sm, Yb) in the molar ratio of 2:1 in THF with subsequent treatment by Na‐K alloy afforded (1‐C₅H₉C₉H₆)₂Ln‐(THF)_n(Ln=Sm, n=1; Ln=Yb, n=2), while the reaction of Sml₂ with K(1‐C₅H₉C₉H₆) in the molar ratio of 1:2 in THF gave the anionic complex K(1‐C₅H₉C₉H₆)₃Sm(THF)₃. The X‐ray structure of (1‐C₅H₉C₉H₆)₂Yb(THF)₂ showed that central metal Yb is coordinated by two cyclopentadienyl rings of 1‐cyclopentylindenyls and two oxygen atoms from two tetrahydrofuran molecules to form pseudo‐tetrahedral coordinate geometry. All these complexes are active for the polymerization of acrylonitrile.     

气相色谱-质谱法测定化妆品中的丙烯腈

建立了化妆品中丙烯腈的气相色谱-质谱分析方法.不同类型的化妆品样品中加入甲醇超声提取,经高速离心处理浓缩后,采用Oasis HLB固相萃取柱净化,1 mL 20%甲醇溶液淋洗,3 mL 80%甲醇溶液洗脱,收集洗脱液,浓缩后经无水硫酸钠脱水,进行气相色谱-质谱定性及定量分析.选用HP-INNOWax(60 m×0.25...     

Effect of Methyl Methacrylate Graft Acrylonitrile–Butadiene-Styrene on Morphology and Properties of Polycarbonate/Acrylonitrile–Butadiene-Styrene Blend

In order to improve the compatibility of polycarbonate (PC) and acrylonitrile– butadiene–styrene (ABS), a new type of reactive compatibilizer, methyl methacrylate graft acrylonitrile–butadiene–styrene (MABS) tetramer, was synthesized. The structure and properties of PC/ABS (70/30) blend with various MABS ratios were studied in terms of their mechanical and morphological properties. The results indicated that with the addition of MABS, the glass transition temperature (T_g) of the PC and ABS phases were closer to each other. Addition of MABS decreased the domain size of the ABS dispersed phase, making the dispersed phase well distributed, and the interfacial cohesiveness was enhanced. Notched impact strength and elongation at break of the PC/ABS (70/30) blend increased remarkably with the addition of MABS, with a small drop in the tensile strength.     

SET‐LRP of acrylonitrile catalyzed by tin powder

Sn(0)‐mediated single electron transfer‐living radical polymerization (SET‐LRP) of acrylonitrile (AN) with carbon tetrachloride (CCl₄) as initiator and hexamethylenetetramine (HMTA) as ligand in N, N‐dimethylformamide (DMF) was studied. The polymerization obeyed first order kinetic. The molecular weight of polyacrylonitrile (PAN) increased linearly with monomer conversion and PAN exhibited narrow molecular weight distributions. Increasing the content of Sn(0) resulted in an increase in the molecular weight and the molecular weight distribution. Effects of ligand and initiator were also investigated. The block copolymer PAN‐b‐polymethyl methacrylate with molecular weight at 126,130 and polydispersity at 1.36 was successfully obtained. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012     

Solution and Solid-State Photophysical Properties of Positional Isomeric Acrylonitrile Derivatives with Core Pyridine and Phenyl Moieties: Experimental and DFT Studies

The compounds I (Z)-2-(phenyl)-3-(2,4,5-trimethoxyphenyl)acrylonitrile with one side (2,4,5-MeO-), one symmetrical (2Z,2′Z)-2,2′-(1,4-phenylene)bis(3-(2,4,5-trimethoxyphenyl)acrylonitrile), II (both sides with (2,4,5-MeO-), and three positional isomers with pyridine (Z)-2-(pyridin-2- 3, or 4-yl)-3-(2,4,5-trimethoxyphenyl)acrylonitrile, III–V were synthetized and characterized by UV-Vis, fluorescence, IR, H¹-NMR, and EI mass spectrometry as well as single crystal X-ray diffraction (SCXRD). The optical properties were strongly influenced by the solvent (hyperchromic and hypochromic shift), which were compared with the solid state. According to the solvatochromism theory, the excited-state (μ_e) and ground-state (μ_g) dipole moments were calculated based on the variation of Stokes shift with the solvent’s relative permittivity, refractive index, and polarity parameters. SCXRD analyses revealed that the compounds I and II crystallized in the monoclinic system with the space group, P2₁/n and P2₁/c, respectively, and with Z = 4 and 2. III, IV, and V crystallized in space groups: orthorhombic, Pbca; triclinic, P-1; and monoclinic, P2₁ with Z = 1, 2, and 2, respectively. The intermolecular interactions for compounds I–V were investigated using the CCDC Mercury software and their energies were quantified using PIXEL. The density of states (DOS), molecular electrostatic potential surfaces (MEPS), and natural bond orbitals (NBO) of the compounds were determined to evaluate the photophysical properties.     

Preparation of hydrogenated natural rubber with nanomatrix structure

Hydrogenated deproteinized natural rubber (HDPNR) with nanomatrix structure was prepared through graft‐copolymerization of acrylonitrile and styrene onto HDPNR particle in latex stage. Structural characterization of the resulting materials through nuclear magnetic resonance and Fourier‐transform infrared spectroscopy confirmed that acrylonitrile and styrene were grafted onto HDPNR. The weather resistance, thermal properties, mechanical properties, storage modulus, and morphology of the resulting materials were investigated in comparison with those of HDPNR. The obtained result indicated that the graft‐copolymerization of HDPNR with hydrogenation conversion of 60 mol% attained the highest grafting efficiency. Thermal resistance and storage modulus of HDPNR‐graft‐poly (styrene‐co‐acrylonitrile) (HDPNR‐g‐SAN) were superior compared with those of HDPNR and deproteinized natural rubber. This was attributed to the nanomatrix formed in HDPNR‐g‐SAN, which was confirmed through a transmission electron microscope. Ribbed smoked sheet natural rubber exhibited the outstanding mechanical properties and weather resistance when it was mixed with HDPNR‐g‐SAN.     

接枝型偕胺肟树脂/SiO_2功能复合微粒的制备

用偶联剂γ-(甲基丙烯酰氧)丙基三甲氧基硅烷(KH-570)对微米级硅胶进行了表面化学改性,采用溶液聚合法,在改性硅胶微粒表面接枝丙烯腈(AN),制备了接枝微粒PAN/SiO2。用盐酸羟胺对接枝PAN进行偕胺肟(AO)化转变,制得了接枝有偕胺肟树脂(PAO)的复合型功能微粒PAO/SiO2。采用红外光谱(FT-IR)、热失重(TGA)及扫描电子显微镜(SEM)等测试技术,对接枝微粒PAN/SiO2以及功能微粒PAO/SiO2进行了表征,考察了制备条件对AN的接枝聚合过程及对PAN的偕胺肟化转变过程的影响规律。结果表明,适宜的接枝聚合条件为:引发剂质量分数为1.5%,反应温度为75℃。接枝聚合5h可制得接枝度为0.14g/g的接枝微粒PAN/SiO2。受偕胺肟基团空间位阻的影响,PAN的偕胺肟化转变反应不能进行彻底,适宜的PAN/SiO2偕胺肟化转变反应条件为:介质pH值为6～7,温度70℃,反应时间4h。所制得的功能微粒PAO/SiO2腈基转化率约为78%。     

以偶氮二异庚腈为引发剂的丙烯腈的低温溶液共聚合

以偶氮二异庚腈为引发剂, 丙烯腈、衣康酸和丙烯酸甲酯为三元共聚体系, 在二甲基亚砜中进行低温溶液共聚合, 合成了高分子量的聚丙烯腈树脂. 通过正交设计的方法研究了反应温度、单体浓度和引发剂浓度等因素对分子量和单体转化率的影响, 得出了相应的最佳工艺配方. 采用红外光谱、核磁共振和凝胶渗透色谱等方法对共聚物进行了表征. 结果表明, 降低聚合反应温度和引发剂的用量以及提高单体浓度均有利于提高共聚物的分子量, 其中引发剂浓度对分子量的影响最为显著.