聚烯烃透明化添加剂二亚苄基山梨糖醇(DBS)系列产品的研制

研究了合成二亚苄基山梨糖醇（ＤＢＳ）、二（对甲基苄叉）山梨糖醇（ｐ Ｍｅ ＤＢＳ）和二（对氯苄叉）山梨糖醇（ｐ Ｃｌ ＤＢＳ）系列产品的投料摩尔比、反应时间、催化剂对甲基苯磺酸和促进剂甲醇用量等因素对ＤＢＳ产品收率和熔点的影响。在苯甲醛（或对甲基、对氯苯甲醛）和山梨糖醇投料摩尔比为２１∶１,对甲基苯磺酸、甲醇用量分别为苯甲醛和山梨糖醇投料总量的１２％和２３６％,反应时间５５ｈ条件下,ＤＢＳ、ｐ Ｍｅ ＤＢＳ和ｐ Ｃｌ ＤＢＳ产品收率大于８０％,熔点分别为２０２～２１６℃、２３０～２４０℃和２４５～２５８℃。     

聚烯烃成核剂二亚苄基山梨糖醇系列产品的合成

研究了合成二亚苄基山梨糖醇(DBS)、二(对甲基苄叉)山梨糖醇(p-Me-DBS)和二(对氯苄叉)山梨糖醇(p-Cl-DBS)系列产品的投料摩尔比、反应用溶剂、催化剂对甲基苯磺酸和搅拌速度等因素对DBS产品收率和熔点的影响。在苯甲醛(或对甲基苯甲醛、对氯苯甲醛)和山梨糖醇投料摩尔比为2.0～2.1∶1.0,对甲基苯磺酸、环己烷用量分别为苯甲醛和山梨糖醇投料总质量的4.0%和550%,反应时间6h条件下,DBS、p-Me-DBS和p-Cl-DBS产品收率大于70%,熔点分别为210～216℃、230～240℃和245～260℃。     

1,3-2,4-二(3,4-二甲基)亚苄基山梨糖醇合成研究

以山梨糖醇与3，4-二甲基苯甲醛为原料，制备1，3-2，4-二（3，4-二甲基）亚苄基山梨糖醇聚丙烯透明化成核剂。在山梨糖醇与3，4-二甲基苯甲醛进料摩尔比为1．0：（2．1～2．2）、反应为5．5～6．5h、搅拌转速为330～350r／min、反应温度为75±5℃的反应条件下，以C6烷烃做反应溶剂，应用特定的反应促进剂和催化剂，反应收率达到95％左右，产物熔程短、纯度高，对PP透明改性效果理想。     

二亚苄基山梨糖醇系列产品的合成

研究了合成二亚苄基山梨糖醇(DBS)、二(对甲基苄叉)山梨糖醇(p-CH3-DBS)和二(对氯苄叉)山梨糖醇(p-Cl-DBS)系列产品的投料摩尔比、反应用溶剂、催化剂对甲基苯磺酸和搅拌速度等因素对DBS产品收率和熔点的影响.在苯甲醛(或对甲基苯甲醛、对氯苯甲醛)和山梨糖醇投料摩尔比为(2.0~2.1)∶1,对甲基苯磺酸、环己烷用量分别为苯甲醛和山梨糖醇投料总质量的4.0%和550%,反应时间6 h条件下,DBS、p-CH3-DBS和p-Cl-DBS产品收率大于70%,熔点分别为210~216℃、230~240℃和245~260℃.     

1,3-2,4-二亚(对甲基)苄基山梨糖醇的合成研究

在14L模式釜中合成出了1，3-2，4-二亚(对甲基)苄基山梨糖醇成核剂，产品收率在98％以上，熔点合格。确定了合成反应的最佳工艺条件为：酸催化剂用量A／S为1．3％左右，反应原料物质的量比为1．9～2．1，反应中要加入“促进剂M”并以方式2加入效果最好，反应时间4．5h，反应初期缓慢加热，中后期加热循环水温度90℃左右。将合成的1，3-2，4二亚(对甲基)苄基山梨糖醇(P-Me-DBS)应用于聚丙烯，结果表明：p-Me-DBS透明效果好于DBS，与进口产品接近。     

1,3∶2,4-二（3,4-二甲基苯亚甲基）山梨醇的制备工艺优化

通过正交实验优化了聚烯烃成核剂HX-3主要成分1,3∶2,4-二（3,4-二甲基苯亚甲基）山梨醇（DMDBS）的制备工艺。在以环己烷（400 mL）和甲醇（60 mL）为溶剂、对甲基苯磺酸（1.0 g）为催化剂、山梨醇（0.15 mol）与3,4-二甲基苯甲醛（0.30 mol）回流反应6 h的优化条件下,DMDBS平均收率达98.9%、熔点≥254.3℃、纯度≥98.17%。在5 L搪玻璃釜中进行23次放大实验,验证了优化工艺,并已在工业化规模生产中成功应用。     

新一代聚丙烯成核剂的合成及应用

介绍了二(3,4-二甲基二苄叉)山梨糖醇(DMDBS)的合成路线和作用机理,并以山梨糖醇和3,4-甲基苯甲醛为原料,在固体酸的作用下,不用分离水就能直接合成出新一代聚丙烯透明成核剂DMDBS.结果表明,在醇醛物质的量比2.1、催化剂加量4.5％(质量分数,以醇醛质量总和为基准,下同)、反应温度25℃、反应时间5h、溶剂...     

1,3:2,4-二(3,4-二甲基苯亚甲基)山梨醇的制备工艺优化

通过正交实验优化了聚烯烃成核剂HX-3主要成分1,3:2,4-二(3,4-二甲基苯亚甲基)山梨醇(DMDBS)的制备工艺.在以环己烷(400 mL)和甲醇(60 mL)为溶剂、对甲基苯磺酸(1.0 g)为催化剂、山梨醇(0.15 mol)与3,4-二甲基苯甲醛(0.30 mol)回流反应6 h的优化条件下,DMDBS平均收率达98.9%、熔点≥254.3℃、纯度≥98.17%.在5 L搪玻璃釜中进行23次放大实验,验证了优化工艺,并已在工业化规模生产中成功应用.     

常温合成3,4-二甲基二亚苄基山梨醇

以D-山梨醇和3,4-二甲基苯甲醛为原料,乙醇为反应介质,在对甲苯磺酸催化下常温合成了3,4-二甲基二亚苄基山梨醇。通过正交实验确定最佳的实验条件为:D-山梨醇与3,4-二甲基苯甲醛摩尔比为1∶1.75;对甲苯磺酸与3,4-二甲基苯甲醛摩尔比为0.7∶1,乙醇为溶剂;反应时间为6h;产率71.0%,熔点270~272°C。经红外光谱对该产品进行了表征。     

1,3;2,4-二(3,4-二甲氧基苄基)山梨醇的合成与表征

以D-山梨醇,3,4-二甲氧基苯甲醛为原料,合成1,3;2,4-二(3,4-二甲氧基苄基)山梨醇的工艺条件。实验表明:采用对甲基苯磺酸(PTSA)作为催化剂,当n(D-山梨醇)∶n(3,4-二甲氧基苯甲醛)=1∶2.0².1,催化剂、环己烷、甲醇用量分别为反应基础物用量的3%、600%、350%(质量分数),反应时间5h左右,产率可达95%以上,并对其结构进行了表征。     

Victrex® poly(ethersulfone) (PES) and Victrex® poly(etheretherketone) (PEEK)

Properties of two high performance engineering thermoplastics, amorphous polyethersulfone (PES) and semicrystalline polyetheretherketone (PEEK), are discussed. Both resins can be processed by conventional techniques, compounded with high performance fibers, and have high service temperature (up to 300°C). Due to the amorphous character PES can be dissolved and spray coated into metals.     

Photopyroelectric Spectroscopic Studies of ZnO-MnO(2)-Co(3)O(4)-V(2)O(5) Ceramics

Photopyroelectric (PPE) spectroscopy is a nondestructive tool that is used to study the optical properties of the ceramics (ZnO + 0.4MnO(2) + 0.4Co(3)O(4) + xV(2)O(5)), x = 0-1 mol%. Wavelength of incident light, modulated at 10 Hz, was in the range of 300-800 nm. PPE spectrum with reference to the doping level and sintering temperature is discussed. Optical energy band-gap (E(g)) was 2.11 eV for 0.3 mol% V(2)O(5) at a sintering temperature of 1025 °C as determined from the plot (ρhυ)(2)versushυ. With a further increase in V(2)O(5), the value of E(g) was found to be 2.59 eV. Steepness factor 'σ(A)' and 'σ(B)', which characterize the slope of exponential optical absorption, is discussed with reference to the variation of E(g). XRD, SEM and EDAX are also used for characterization of the ceramic. For this ceramic, the maximum relative density and grain size was observed to be 91.8% and 9.5 μm, respectively.     

(Ba_(1-α)Sr_α)_(4.8)(Sm_(0.7)La_(0.3))_(8.8)Ti_(18)O_(54)陶瓷的微波介电性能

采用固相合成法制备了(Ba(1-α)Srα)4.8(Sm0.7La0.3)8.8Ti18O54(α=0.1～0.5)系陶瓷,表征了该陶瓷的相组成和显微结构,测试了微波介电性能.结果表明:α=0.3时,(Ba(1-α)Srα)4.8(Sm0.7La0.3)8.8Ti18O54系陶瓷为单相的新钨青铜结构固溶体.α>0.3时,相继出现了第二相BaLa2Ti4O12和La0.66TiO2.993.随α的增加,(Ba(1-α)Srα)4.8(Sm0.7La0.3)8.8Ti18O54系陶瓷的相对介电常数(εr)先增大后有所波动,品质因数(Qf)先增大后减小,谐振频率温度系数(τf)单调减小.α=0.3时,在1 350℃烧结的陶瓷的微波介电性能最佳:εr=98.77,Qf=5184GHz,τf=10.9×10-6/℃,优于不掺杂的BaO-Sm2O3-TiO2陶瓷的.     

Calcium silicate hydrate (II) (“C-S-H(II)”)

This semicrystalline phase, originally named ‘calcium silicate hydrate(II)’ by Taylor (1950), has been studied with X-rays, electron optics, chemical investigation of silicate anion type, infrared spectra, and thermal methods. It is structurally related to jennite (C₉S₆H₁₁) and probably also to the fibrous CSH of cement pastes, the three phases forming a sequence of decreasing crystallinity. The specimen studied had approximate composition C₂SH_3.2 after standing over saturated CaCλ₂ at about 15°C. CSH(II) contains metasilicate chains and pyrosilicate groups and has a disordered layer structure. Much of the water can be lost reversibly without significant change in lattice parameters.     

Poly(butadiene-acrylic acid(g)acrylonitrile(g)acrylic acid)

Summary In the present work we describe, the synthesis and characterization of a new gel obtained by crosslinking a cooligomer of butadiene-acrylic acid (BuAA), by reaction with acrylonitrile and acrylic acid. The purified product was characterized by FTIR, elemental analyses and scanning electronic microscopy. The thermal properties were studied and swelling indexes were determined in different solvents and at different pH values. The capacity of poly(butadiene-acrylic acid(g)acrylonitrile(g)acrylic acid) [gel A] to separate different organic substances, such as amino acids and colorants, was determined.     

Photooxidative stability of substituted poly(phenylene vinylene) (PPV) and poly(phenylene acetylene) (PPA)

The addition of side groups to improve the photooxidative stability of polymers used in polymer-based light-emitting diodes (LEDs) is explored. Infrared spectroscopy and computational chemistry techniques are used to study the effects of chemical substitution of the reactive vinylene moiety in poly(phenylene vinylene) (PPV). The bond order of the vinylene group in small oligomers is calculated using semiempirical techniques to assess the improvement in stability toward oxidants such as singlet oxygen. We find that PPV dimers allow relative comparisons across a range of possible substitutions. Experimental results correlate well with these calculations. The addition of electron-withdrawing substituents, such as nitrile groups, to the vinylene moiety is found to be particularly effective in reducing the reactivity of alkoxy-substituted PPV toward singlet oxygen. The photooxidative stability of a poly(phenylene acetylene) (PPA) derivative is also studied. It appears that this family of polymers is more stable toward photooxidation than are its PPV analogs. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 69: 2451–2458, 1998     

Chemical cross-linking of conducting poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) using poly(ethylene oxide) (PEO)

Hybrid films of poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) were prepared with different molecular weights of poly(ethylene oxide) (PEO). The cross-linking reaction between PEO and PEDOT:PSS was performed at high temperature and confirmed by using differential scanning calorimeter (DSC), contact angle measurement, and solid-state ¹H NMR. The effect of chemical reaction on the conductivity and morphology of these hybrid films was studied by using 4-point probe and atomic force microscope (AFM), respectively. As-spun PEO/PEDOT:PSS films have lower electric conductivity due to the addition of nonconductive PEO, and exhibits no molecular weight dependence on conductivity. After chemical cross-linking reaction at high temperature, only PEDOT:PSS films with lowest molecular weight PEO additives show enhanced conductivity with increasing reaction time. AFM result indicates that the heat-treated PEO/PEDOT:PSS hybrid films show grain-like morphology compared to ethylene glycol treated PEDOT:PSS films which shows continuous PEDOT domain. In the present work we demonstrate that the cross-linking reaction can be used to improve the wet stability of PEDOT:PSS nanofiber, showing good water resistance and excellent dimensional stability.     

Thermal studies of blends of poly(phenylene sulfide) (PPS) with poly(phenylene sulfide sulfone) (PPSS) and with poly(phenylene sulfide ether) (PPSE)

The miscibilities of poly(phenylene) sulfide/poly(phenylene sulfide sulfone) (PPS/PPSS) and poly(phenylene) sulfide/poly(phenylene sulfide ether) (PPS/PPSE) blends were invesigated in terms of shifts of glass transition temperatures T_g of pure PPS, PPSS, a dn PPSE. The crystallization kinetics of PPS/PPSS blends was also studied as a function of molar composition. The PPS/PPSS and PPS/PPSE blends are respectively partially and fully miscible. PPSE shows a plasticizing effect on PPS as does PPS on PPSS, which necessarily improves te processibility in the respective systems. We can control T_g and melting temperature T_m of PPS by varying amounts of PPSE in blends. The melt crystallization temperature T_mc of PPS/PPSE blends was higher than that of the PPSE homopolymer. Therefore, these blends require shorter cycle times in processing than pure PPSE. The overall rate of crystallization for PPS/PPSS blends follows the Avrami equation with an exponent ?2. The maximal rate of crystallization for PPS/PPSS blends occurs at a temperatre higher by 10°C than that for PPS, while the crystallization half time t_1/2 is 4 times shorter. In the cold crystallization range, crystal growth rates increase and Avrami exponents decrease significantly as the temperature increases.