Study of siloxane additives migration to the surface of polyester-(melamine)-polyurethane coatings: Aging effects after ethanol cleaning

This study determines the influences of siloxane flow agents’ migration on the outermost surface composition of clearcoats, before and after ethanol cleaning. This evaluation is undertaken to improve adhesion of pressure-sensitive adhesives (PSAs) on automotive paint systems. Most of the siloxane flow agents segregate from the bulk to the clearcoat outermost surface during curing. These additives can cover until 50% of the surface area but X-ray photoelectron spectroscopy (XPS) and time of flight-secondary ion mass spectrometry (ToF-SIMS) analyses indicate that they can be removed by ethanol cleaning. Composition of the cleaned clearcoats surfaces are similar as the composition of clearcoat formulated without siloxane additives: the polyester-(melamine)-polyurethane network is more detected than before cleaning. However, outermost surface analyses show that several aging weeks increase the siloxane additives segregation. This post-cleaning migration modifies the clearcoat surface composition and cancels the chemical modifications due to the ethanol cleaning. XPS analyses show that silicon concentrations after cleaning and aging are inversely proportional to the initial silicon concentrations measured after curing. It highlights that aging has to be controlled to improve adhesion of PSAs on clearcoats. A second ethanol cleaning on aged clearcoats is not effective to remove these new siloxane additives. Their formulation should be different from the flow agents and it could modify their solubility in ethanol. This result could also indicate that these new siloxane additives are not located on the last molecular layer of surface and they would not be soluble in ethanol.     

DSC study of transitions involved in thermal treatment of foamable mixtures of PE and EVA copolymer with azodicarbonamide

The transitions and reactions involved in the thermal processing of binary mixtures of polyethylene and poly(ethylene‐co‐vinyl acetate) copolymers with different concentrations of a foaming agent (azodicarbonamide) were studied using differential scanning calorimetry (DSC). The effect of ZnO as a kicker also was discussed. The temperature at the maximum rate and the heat evolved were measured for all the processes—melting, transitions, and reactions—all the mixtures prepared were measured and compared. Azodicarbonamide decomposed differently depending on the polymeric matrix. These data can be very useful for the plastic processing industry. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 2015–2025, 2006     

Effect of Impurities on the Syndiospecific Coordination Polymerization of Styrene

Summary: The effect of impurities on the coordination polymerization has generally been classified and discussed in different ways and has been investigated in detail in the syndiospecific homo‐ and copolymerization of styrene. With regard to impurities of styrene, phenylacetylene as an unpolar impurity containing separate multiple bonds, 1‐phenyl‐1,2‐ethanediol and ω‐hydroxyacetophenone as examples of polar impurities, and ethylbenzene as an other unpolar impurity have been investigated regarding the effect on the polymerization rate and the influence on the molecular properties of the syndiotactic polystyrenes. In the syndiospecific copolymerization with p‐methylstyrene, indene shows a different behavior regarding the decrease of the polymerization conversion depending on the comonomer concentrations present in the monomer mixture. Additionally, the effect of impurities of the catalyst system on the syndiospecific styrene polymerization has been demonstrated, particularly of octahydrofluorene as a component of the transition metal compound and of trimethylaluminium as a component of the cocatalyst methylaluminoxane. All results have been discussed with respect to the mechanisms of the effects on polymerization behavior and on polymer properties.

Dependence of the relative polymerization conversion on the amount of indene added to the monomer mixture in styrene (ST)/p‐methylstyrene (PMS) copolymerization (catalyst n‐ratio: 0.5; molar ratio MAO:Ti = 110:1; polymerization temperature: 60 °C; polymerization time: 45 min).     

洗发、护发产品功能添加剂

综述了洗发、护发二合一香波的功能添加剂。从消费者对产品的诉求着手，介绍了改善泡沫润滑感、泡沫稳定性的非离子水溶性聚氧乙烯醚聚合物，改善头发干、湿梳理性及柔软性的阳离子聚合物、阳离子表面活性剂和聚二甲基硅氧烷，维持香波在货架期内稳定的悬浮稳定剂、防腐剂，以及赋予洗发、护发二合一香波附加功能的去屑成分、防晒成分和头发营养滋润成分等。     

电子辐射对渗透和非渗透性客体上指纹信息记录的影响

由于恐怖分子利用邮政系统投寄携带炭疽病毒的邮件,传播病毒,已引起美国政府在邮政系统,选择地利用电子辐射杀死病毒。然而,这种病毒袭击并没有得到有效控制,却使信封内的邮件由于高温辐射,受到损坏。有报道说,由于电子辐射使纸张、珠宝、信用卡、软盘和光盘及其它电子材料受到损害。某些研究已在法庭科学中得到验证。本文介绍辐射过程在渗透和非渗透性客体上,对化学试剂、生物酶记录指纹信息的影响。     

Rheological properties and foam processibility of precured EPDM

EPDM foam was prepared by dynamically vulcanizing EPDM compound in a HAAKE rheometer firstly, then mixing the partially precured EPDM compound with a blowing agent and a sulfur vulcanizing system on a two roll mill. The compound was extruded through a cold feed extruder, and the extrudate was foamed in a circulating hot air oven. EPDM compound was vulcanized partly in the HAAKE rheometer, the final torque increases with increasing sulfur content. Rheological measurement shows the dynamic storage modulus, the loss modulus, and the complex viscosity of precured EPDM compound increase with increasing sulfur content. Then the partially precured EPDM compound was compounded with a blowing agent and a sulfur vulcanizing systems, Rheometric measurement shows that the rate of vulcanization of partially precured EPDM compound is not affected by the precure. The blowing results show that the foam processibility could be improved and the expansion ratio increases in the same processing condition for optimum partially precured EPDM compound, which indicates the optimum crosslink density for EPDM could enhance the efficiency of blowing agent AC. SEM shows that the foam articles have a closed‐cell structure with few open cells, and the large cells inlay among the small cells. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 3387–3394, 2006     

新型聚氨酯防水涂料性能的研究

本以聚醚多元醇和过量多异氰酸酯合成聚氨酯预聚体，以水为固化剂制备一种新型聚氨酯防水涂料，讨论了两种聚醚多元醇(N220／N3050)质量比、NCO质量分数、固化剂含量、甲乙两组分质量比对聚氨酯防水涂料力学性能的影响。     

Surface functionalized colloidal silica particles from an inverse microemulsion sol gel process

Colloidal silica particles are prepared via a sol gel technique carried out in an inverse microemulsion of water in a toluene solution of tetraethoxysilane (TEOS), stabilized by either an anionic surfactant AOT or isopropanol. Functionalized material was obtained using a functional coupling agent (RO)₃Si(CH₂)₃ X, X being a functional group such as methacryloyl, thiol, vinyl, amino group, or a chlorine atom. Functionalization can be carried out either directly via the direct copolycondensation of TEOS and the coupling agent, or in a two-step process involving a core-shell polycondensation of the coupling agent onto preformed silica particles. Kinetic studies of the copolycondensation are carried out using either²⁹Si NMR analysis or liquid chromatography. They show that the consumption of TEOS is more rapid than that of the coupling agent. The materials are characterized both chemically (elemental analysis, FTIR,¹³C and²⁹Si NMR CPMAS analysis), and by their particle size. The silica functionalized with a polymerizable methacryloyl group is encapsulated by a polymer layer in an inverse emulsion polymerization of acrylic acid. After inversion of the emulsion in water, the resulting material is covered with a layer of hydrophobic polymer in a conventional emulsion polymerization.     

氨纶用聚酯二醇的研究

本文研究了聚酯二醇的生产工艺,重点研究了反应温度对生产工艺的影响以及原料已二酸与二元醇的投料比对产品酸值和羟值的影响,催化剂对产品质量的影响,并对产品着色原因进行了探讨。     

JX系列高温脱氯剂的开发

通过脱氯剂穿透氯容随实验条件变化规律的研究，讨论高温脱氯剂的脱氯反应模型。基于对脱氯机理的认识，通过对活性组份筛选和制备方法研究，成功研制出以JX-5A脱氯剂为代表的JX系列高温脱氯剂，穿透氯容达到50％以上。