粘胶纤维和Lyocell纤维生产中溶解机理的探讨

溶解技术是纤维素纤维制造过程中关键的技术，溶解的效果直接影响过滤、纺丝成形和最终产品的质量。纤维素溶解的详细机理非常复杂，但基本上都可以从分子间氢键的破坏方面得到解释，本文着重就粘胶纤维和Lyoeell纤维生产中纤维素不同的溶解过程和溶解机理作了初步探讨。     

涤纶快速染色和Polycron Dianix染料

涤纶的快速染色对于缩短工时、增加生产和降低能耗具有重要的作用,但其关键是必须注意增进重现性和匀染性才能保证纺织产品的质量。通过对分散染料-涤纶染色机理的系统分析,提出了一种快速染色方法,并证明使用选择的PolycronDianix染料是有效的。一、染色机理分散染料的染色机理可用以下方式表示:(1)染料在染浴中的分散↓(2)单分子在水中的溶解↑(溶解速率)↓(3)纤维表面的吸附↑(吸附速率)↓(4)向纤维内部的扩散↑(扩散速率)其中第四步(扩散速率)主要决定染色速率,但并不能完全控制染色速率,因为使用了小浴比和高竭     

关于高聚物共混的几个问题

阐述了有关高聚的共混研究中几个问题和有关概念的见解；相容是在不相溶（相分离）的前提下考察的问题，属相分离动力学范畴；存在二种溶解，即分子链段（或链节）的溶解和分子的溶解，结晶相分离是结晶高聚物共混体系的主要特征；以及两种结晶高聚物的晶相间偶联，结晶作用与共混效应之间的相互关系等。     

基于分子修饰C-COS的高吸湿保湿机理

采用漆酶/2,2,6,6-四甲基哌啶-1-氧自由基(TEMPO)体系氧化壳寡糖制备了一种高吸湿保湿性羧基化壳寡糖(C-COS)。利用低场核磁共振(LF-NMR)、FTIR和13CNMR考察了其分子间氢键的变化并进一步推测出吸湿保湿机理。结果表明:在C-COS的吸湿过程中,聚合物分子与水之间存在着分子间氢键作用力。C-COS分子上极性较强的羧酸根产生了新的氢键效应,结合升温红外中3363、1643 cm~(–1)处吸收峰强度的减小和同样波数下吸收峰频率的蓝移以及溶胀红外中1643cm~(–1)处吸收峰强度的增加,确定了C-COS分子中羧酸根与水之间所形成的水合氢键(H—O—H···O—C==O)。另外,C-COS的保湿机理在于聚合物溶解在水体系中能够形成一种巨大的聚合物-水网状结构,促使水分子以氢键的形式被牢牢地锁住在这种网状结构中。     

聚碳硅烷的高温高压生成机理研究II蒸馏产物的结构分析

以液态聚硅烷(LPS)在450℃反应得到的聚碳硅烷(PCS)粗产品为原料,经溶解、过滤、热处理后减压蒸馏,收集蒸馏馏分并进行表征,由此推出不同摩尔质量的PCS的典型结构,进而推测出LPS转化为PCS分子的机理是:随着温度的升高,LPS中的Si—Si键发生断裂、重排,转化为Si—C键,生成低分子碳硅烷;随着温度的继续升高,碳硅烷分子间发生脱氢、脱甲烷缩合反应,摩尔质量逐渐长大,生成PCS。     

氯化聚丙烯研究进展

在叙述氯化聚丙烯合成与改性的基础上,综述了氯化聚丙烯的氯化度、分子结构和分子质量与其溶解性能、热行为、 相容性等性能的关系;并按照氯化聚丙烯的研究过程,将其对聚烯烃塑料的附着机理研究分为分子结晶性相互作用机理、色散 机理和分子缠结机理3个阶段,并进行了总结;同时对氯化聚丙烯应用的新进展和研究开发方向也作了评述。     

卤化物在合成亚硫酸金盐溶金过程中的作用

用离子交换膜电解法研究了金在Na2SO3溶液中加入Cl-、Br-后的阳极溶解机理.结果表明,在Na2 SO3溶液中加入Cl-和Br-后,由于竞争配位作用可以加快金的溶解速率.Br-在阳极表面被氧化生成初生态Br2,Br2可以快速氧化阳极金从而更有效地抑制SO32-氧化,有利于获得高纯度Na3 Au(SO3)2溶液.     

静压釜的溶解机理及影响因素

描述了静压釜溶解机理及影响因素。详细阐述了静态法溶解泡花碱5个过程的机理,提出水合、一次溶解、水解、二次溶解、电离是相辅相成不可分割的复杂过程。探讨了模数、温度与压力、水料比、固体料粒度几个主要因素对泡花碱(硅酸纳)溶解的影响,并解决了融化过程中存在的问题进行了优化,完善了静态溶解泡花碱实际操作过程。     

纤维素在氯化锂—N,N二甲基乙酰胺溶剂系中溶胀与溶解的影响因素(摘)

在纤维素、氯化锂(LiCl)、N.N二甲基乙酰胺(DMAc)体系中,LiCl分子与纤维素分子中葡葡糖残基的摩尔比大于3左右,纤维素才可能形成真溶液。LiCl/DMAc溶剂体系中含少量水份,能加快纤维素在其中的溶解;溶剂体系中含过多的水分,便失去溶解纤维素的能力。适当升高纤     

氯化锌法制造活性炭的机理探讨

在化学法生产活性炭中,氯化锌作为活化剂显示出优良的效果,其主要原因是氯化锌能溶解纤维素,氯化锌溶解纤维素的机理是氯化锌能作为电子对的给予体和接受体中心与纤维素复合体的-OH基发生作用,导致纤维素分子间的链的断裂。     

Novolak resins with high thermal stability,high resolution,improved photospeed and etch characteristics for advanced photoresist applications

Novolak resins provide the best overall performance for “g” and “i”-line photoresists. There is a continuing need for advanced novolak designs that will provide improved lithographic, thermal, and etch characteristics that may be reproducibly synthesized. A novolak synthesis process was developed using the solution condensation technique. Cresol mixtures with m-cresol and 3,5-xylenol at specific ratios provide reproducible novolaks with controlled molecular weights. In order to achieve high thermal and etch performance, while retaining photospeed and resolution characteristics, three basic approaches were investigated: (1) increase in molecular weight, which produces novolaks with T_g ranging from 120 to 130°C with relatively slow dissolution rates; (2) incorporation of multi-hydroxyphenols such as resorcinol to tailor the dissolution rate, resolution, thermal, etch, and adhesion characteristics; (3) partial esterification of multi-hydroxy novolaks giving a T_g range of 140 to 150°C. Lithographic evaluation of the novolak resins was performed by formulating with a 2,1,4-diazonaphthoquinone (DNQ) sensitizer. Results on resin synthesis, molecular weights, lithographic, thermal, and etch characteristics are discussed.     

Novolak design concept for high performance positive photoresists

Novolak resins have been optimized for high performance positive photoresists. Low molecular weight novolak resins are the key components for improving resolution capability, sensitivity, and heat resistance of positive photoresists. Various phenolic compounds (monomers) and oligomers of metacresol novolak resins were evaluated as low molecular weight components. It was found that phenolic compounds that have moderate hydrophobicity and azocoupling capability with diazonaphthaoquinone compounds greatly improve positive photoresist performance. This is explained in terms of the Stone wall model for positive photoresist development.     

Dissolution inhibition mechanisms of naphthoquinone diazides

Dissolution inhibition mechanisms of naphthoquinone diazides in novolak based positive photoresists were investigated from three different aspects:

• ? Dipolar interaction.
• ? Interfacial chemical reactions.
• ? Chemical structures of naphthoquinone diazides.

The results suggest that there exists a hydrogen bonding interaction between the compounds with the matrix novolak resin and that naphthoquinone diazides would crosslink the resin in contact with an alkaline developer, both of which contribute to dissolution inhibition mechanisms. However, there seems to exist another dissolution inhibition mechanism; namely, 1,2-naphthoquinone diazide does not inhibit dissolution of the matrix novolak resin at all while a clear dissolution inhibition effect Is observed for its derivatives containing sulfonyl groups. In the present paper, three dissolution inhibition mechanisms of naphthoquinone diazides will be proposed.     

Effects of diazonaphthoquinone groups on photosensitive coating

Diazonaphthoquinone (DNQ)‐novolak photosensitive materials are important in lithography. DNQ groups play an important role in the photosensitive coating. However, there are no reports on the relationship between content of DNQ groups and properties of the coating. The properties include alkali resistance, isopropanol resistance, and abrasion resistance, the key factors in lithography. The experimental results show proper content of DNQ groups can ensure higher sensitivity, finer resolution, and better abrasion resistance in lithography. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Novolak resins: structure elucidation by multidimensional NMR techniques and correlation with lithographic performance

Photo‐active chemicals blended with novolak resins, solvents and certain other additives serve as photoresists and are the real workhorses of the burgeoning microlithography industry, which plays a key role in making electronic circuits for ICs and VLSIs at micron and sub‐micron levels. It has been realized over the years that the microstructure of these matrix polymers (novolak resins) is very crucial for better lithographic performance. Although various analytical techniques exist for characterizing novolak resins, precise and unambiguous structural details are obtained only through NMR experiments. In this paper, we review the applications of a range of NMR experimental techniques to the structure elucidation of novolak polymers and co‐polymers. Such information is seen to lead to the design of high‐performance photoresists. The optimum percentage of the different phenolic units in novolak resins, which is very crucial for lithographic performance, can also be determined using these spectroscopic techniques. Using DEPT and INEPT ¹³C NMR spectra of novolak resins, two formulae have been developed for quantitative estimation of the lithographic performance of photoresists. On the basis of a comparison of the NMR spectra of a photoresist before and after photolysis, the mechanism of action of a photoresist can be probed, and this should lead to a deeper insight into the design of high‐performing photoresists. Copyright © 2003 Society of Chemical Industry     

The chemistry of g-line photoresist processes

The chemistry that underlies positive imaging, Image Reversal (ImRe) and Built In Mask (BIM), has been investigated. For this purpose the photoactive compound 2, 1 -diazonaphthoquinone-5-(4-cumylphenyl)-sulfonate (PAC-5), the corresponding indenecarboxylic acid (ICA-5) and the decarboxylated derivative of ICA-5 (indene), were isolated and characterized. The study revealed that dissolution of ICA-5 in aqueous base developers gives rise to the formation of an indenyl carboxylate dianion, which decarboxylates in several hours. In the case that ICA-5 is dissolved in weakly alkaline media or in organic solvents such as methanol, the formation of this ion does not occur, but the rate of decarboxylation is almost the same. It is suggested that the decarboxylation reaction proceeds via the indene carboxylate monoanion, which reacts to indenyl anion. The latter is a strong base and is readily protonated to give indene (two isomers). In the case of aqueous base this leads to precipitation of the indene. In agreement with the finding that the indene derived from ICA-5 does not dissolve in aqueous base developers, it was found that mixing indenes into novolak has a considerable inhibitive effect on the dissolution rate of a layer of this material in aqueous base. After a bake (in ImRe this would be the reversal bake), the dissolution rate is almost the same as for unexposed photoresist. Similar experiments with mixtures of novolak and indenecarboxylic acid revealed that there is no difference in the dissolution rate of such layers as compared with exposed photoresist. This excludes the putative effect of porosity, caused by nitrogen extrusion. In the case that 1-phenyl-3-morpholinotriazene is added to the photoresist (in order to produce a dye in the BIM concept), azo-dyes are formed by coupling of diazonium ions on the 1- and 3-position of 3-indenecarboxylic acid. The paper starts with a brief review of the mechanisms of photolysis of 2, 1 -diazonaphthoqui nones, as have been proposed in the literature. Although the formation of ketene as an intermediate is generally accepted, there appears to be no consensus about the existence of carbene.     

Positive‐tone,aqueous‐developable,polynorbornene dielectric: Lithographic,and dissolution properties

A positive‐tone, aqueous base soluble, polynorbornene (PNB) dielectric formulation has been developed. The photolithographic solubility switching mechanism is based on diazonaphthoquinone (DNQ) inhibition of PNB resin functionalized with pendent fluoroalcohol and carboxylic acid substituents. The optical contrast (at 365 nm) was found to be 2.3. The maximum height‐to‐width aspect ratio of developed line and space features was 3 : 2. The sensitivity, D₁₀₀, of a formulation containing 20 pphr of DNQ photoactive compound (PAC) was calculated to be 408 mJ cm^?2. The effects of the PAC molecule structure on miscibility and dissolution of the photosensitive films in aqueous base developer were studied. The effect of the monomer composition of the PNB polymer on the dissolution rate of the formulated PNB resin was evaluated. A unique dissolution and swelling behavior was observed. The effect is attributed to a copolymer synthesized with two monomers each of which is susceptible to deprotonation in aqueous base. FTIR measurements showed that the pure PNBFA has a small percentage of free hydroxyl groups, which did not change appreciably by the addition of PAC to the mixture. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

超硬材料磨具用烯丙基化酚醛改性双马来酰亚胺树脂的研究

A novel thermosetting resin system for superabrasives based on novolak and bismaleimide （BMI） was developed. The novolak resin was allylated and then copolymerized with BMI. The structure of allyl novolak and reaction mechanism were analyzed by FFIR. Thermal and mechanical properties were characterized by using com- prehensive thermal analyzer （DSC-TG） and strength tester, respectively. The results showed that high molecular weight of novolak was advantageous for heat-resistance, but was unfavorable for the bending strength. High allyl content improved the heat-resistance but lowered the bending strength. When the molecular weight of novolak was 450 and allyl content was 50%, the best resin system with good heat-resistance and bending strength was obtained. It was suitable for the manufacturing of superabrasive tools.     

Masking effect of photoactive compounds with various ballast molecules in novolak-naphthoquinonediazide positive photoresists

We investigated the masking effect, that is, the dissolution inhibition effect, of photoactive compounds (PAC) with various ballast moelcules in novolak-naphthoquinonediazide positive photoresists. Two types of ballast molecules were examined: hydroxybenzophenones (HBP) and several m-cresol novolak resins (MCN) of different molecular lengths. The number of naphthoquinonediazide sulfonic (NQDS) moieties in the resist film and the average esterification value of the PACs were the same for each type of ballast molecule. The smaller the size of the HBP ballast molecule, the larger the masking effect becomes. As the size of the ballast molecule becomes smaller, the number of PACs increases and the degree of dispersion of the NQDS moieties in the resist film increases. At the same time, the longer the MCN ballast molecule, the larger the masking effect becomes. The distance between the NQDS moieties in the MCN ballast molecule is greater than that in the HBP ballast molecule. The masking effect per NQDS moiety in the MCN ballast molecule is larger than that in the HBP ballast molecule. As a result, the distance between the NQDS moieties in the ballast molecule and the degree of dispersion of the NQDS moieties in the resist film control the masking effect, which depends on the probability of existence of NQDS moieties around the alkali-soluble hydroxyl groups of the novolak resin. The molecular length of the ballast molecule influences the degree of entanglement with the novolak resins and promotes the masking effect.     

The role of the latent image in a new dual image,aqueous developable,thermally stable photoresist

A new dual image, aqueous developable photoresist can be processed to yield either positive or negative images that are crosslinked and thermally stable to temperatures >300°C. Positive images have similar resolution and processing parameters to conventional positive novolak resists. Negative resists from this system have a number of new and interesting properties that surpass the capabilities of their positive counterparts. In addition to producing highly resolved submicron images, thick coatings of resist can be used to form images with high aspect ratios. By adjusting the exposure of the resist, images with inward sloping wall profiles can be realized. As a result of the images being crosslinked and Insoluble in the resist coating solution, images can be recoated and new images formed over the top of existing patterns to form structures. A hypothetical mechanism that suggests that resist defects caused by dust on the mask or photoresist surface can be reduced In negative mode processing is also presented.