橡胶防焦剂CTP的合成

讨论了以环己醇为原料,以120^#汽油为溶剂,用酞酰亚胺与氢氧化钠生成亚胺钠的方法合成橡胶防焦剂CTP的工艺过程及工艺条件。研究了通氯量、通氯速率、原料配比等工艺条件对反应的影响,确定了生产的最佳工艺条件,提高了产品的质量。     

半芳香族尼龙的制备方法

以尼龙6T为例进行工业小试,采用"水溶液成盐—固相缩聚—硫酸湿法纺丝"的工艺路线,以PTA和HMD为原料,制得熔点为375℃的半芳香族尼龙。介绍了反应机理流程和装置,并对成盐工艺、缩聚工艺、纺丝工艺进行了研究。。     

正交试验法优选花生壳中木犀草素提取工艺

研究了优化花生壳中木犀草素的提取工艺条件。通过正交试验,以提取物中木犀草素的含量为评价指标,优选提取工艺。确立了以质量浓度为70％乙醇、料液比1：10、提取3次、每次时间2h为优选工艺,花生壳中木犀草素能被有效提取。该工艺简捷,经济,可行,适合工业化生产。     

CO_2-DMC产业链碳足迹分析

基于全生命周期法(LCA)对CO_2-DMC(碳酸二甲酯)产业链碳足迹进行了分析,分别以常规反应塔工艺、膜反应塔工艺和反应精馏塔工艺为对象,考察了各工艺在不同能源供应情景下产业链的碳足迹情况,对原料的获取、原料的运输、燃料的使用、燃料的运输以及产品的配送等环节进行了碳足迹分析。结果表明:3种工艺中反应精馏塔工艺能耗、碳足迹最小,常规反应塔工艺最大;以渣油为燃料常规反应塔工艺单位产品碳足迹最大,碳足迹为1.67 t CO_2/t DMC,以天然气为燃料的反应精馏塔工艺碳足迹最小,单位产品碳足迹为0.70 t CO_2/t DMC;燃料消耗碳足迹在总碳足迹中占比最大,其次为原料上游排放。     

石脑油催化加氢工艺研究

介绍了石脑油催化加氢处理和加氢裂化工艺技术,重点介绍了石脑油加氢裂化技术,包括单段加氢裂化工艺、两段加氢裂化工艺、单段串联工艺;描述了国内外石脑油催化加氢催化剂的种类、研究和开发,国外以UOP和Chevron公司为代表,国内以抚顺石油化工研究院(FRIPP)为代表;探讨了石脑油催化加氢工艺现存问题—石脑油加氢反应器降压升高的原因及目前根据实际工艺情况可采取的部分解决方案。     

新型配位剂对化学镀铜工艺的影响

在以柠檬酸钠为配位剂、次磷酸钠为还原剂的化学镀铜工艺的基础上,加入一种新型配位剂,研究了新的化学镀铜工艺。比较了新化学镀铜工艺与传统的化学镀铜、化学镀镍工艺的不同。结果表明:新型化学镀铜工艺沉积速率快、镀液稳定性好、成本低,是很好的代镍工艺。     

乙酸甲酯与甲醇共沸物催化精馏水解工艺

以乙酸甲酯与甲醇共沸物为原料,采用阳离子交换树脂为催化剂,研究了乙酸甲酯催化精馏水解工艺。在实验中以捆扎包作为催化剂的装填方式,系统地研究了催化精馏段和提馏段的高度、进料位置、进料中含甲醇、水酯物质的量比、回流进料比和空速等对酯分解率的影响,获得了最佳的工艺条件。分析了传统的水解分离工艺,提出了可行的新工艺。在最佳工艺条件下,新工艺系统的能耗比传统的固定床工艺降低39.99%。     

德士古煤气化和壳牌煤气化工艺生产甲醇的综合技术经济比较

为选择以煤为原料生产甲醇的气化工艺,采用不同煤种,分别运用德士古煤气化工艺和壳牌煤气化工艺进行了综合技术经济对比;阐述了2种工艺路线的煤质特性、装置能力、工艺技术方案、公用工程单元配置、能耗、成本、投资以及工厂的经济效益。     

利用大同烟煤生产柱状活性炭的工艺开发

研究了以大同烟煤为原料生产柱状活性炭的工艺,讨论了炭化最终温度、活化温度和活化时间等对工艺的影响,给出了最佳工艺条件。     

二溴青酶烷砜酸脱溴制备舒巴坦的工艺研究

本文对以6-APA为原料制备舒巴坦的了研究,分别对以锌、镁为还原剂工艺和以镍、钯碳为催化剂的氢气还原工艺进行了比较和研究,得出以钯碳为催化剂,在0.2MPa下,以氢气为还原剂对二溴青酶烷砜酸进行脱溴还原工艺具有比较明显的优势,制得β-内酰胺酶抑制剂--舒巴坦的收率可达到86.5%.     

Effect of Resin System Parameters on Resin Transfer Molding of Vinyl Ester Based Composites—A Statistically Designed Study

Although the area of composites has advanced significantly over the past three decades, there is still a lack of understanding as to the coupling between materials and processing variables, especially as related to the use of resin systems in emerging processes such as resin transfer molding (RTM). As materials are tailored through the use of additives to resin systems, intricate fiber architectures, and the use of specific processing parameters, the need for a thorough understanding of the effect of minor variations in the materials system and the ultimate need for process control techniques increases. The current investigation is aimed at developing an understanding of variation in performance in three similar vinyl ester resin based composite systems as a function of mold release agent concentration, presence of a wetting/dispersion agent, and preform tool temperature. It is seen that the concentration of mold release agent has a significant influence on performance, which can be correlated with results of dynamic mechanical analysis tests. The importance of using statistically based studies to determine optimum settings and overall variation in performance is emphasized. This approach is favored over the use of an n[sgrave] approach, which gives the user a means of controlling quality based on postproduction control rather than through the selection of settings that are insensitive to variation in the quality of incoming material process changes. The achievement of quality through control of material and process variables is important not only for the cost-efficient production of composite parts but also for the fabrication of large parts such as would be needed for civil infrastructure applications (bridge decks, piers, etc.), where postproduction rejection would result in significant losses.     

基于LOM原型的“金属树脂”模具材料的研究

研究了以快速造型中的ＬＯＭ原型为母模、以金属粉末和环氧树脂为基料的“金属树脂”模具材料性能及其影响因素,比较了各种配方材料的性能,获得了较理想的、适于快速造型ＬＯＭ原型转制工艺的“金属树脂”模具材料配方。     

Optimization method to select temperature based on chemorheological and exothermal reaction of RTM

Heating mold and resin have been widely used in resin transfer molding (RTM) to improve injection and manufacturing efficiency. The unreasonable mold/resin temperatures sometimes lead to excessive viscosity of resin and premature curing, which will result in failure of the filling process. Selection of optimal mold and resin temperature has become a source of concern in the polymer industry. This article presents an optimization method to select mold and injection resin temperatures by using numerical simulation based on chemorheological and exothermal reaction of the RTM process. The results show that the optimization method has high computational efficiency for three-dimensional parts with different shapes. The selected mold/resin temperature ensures the smooth filling process, which provides a powerful tool for parameter design in polymer industry. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 48245.     

环氧树脂浇注成型工艺及模具设计

环氧树脂浇注成型工艺及模具设计是一门综合性的技术。浇注工艺、模具设计制造技术等都能给浇注件的质量产生很大的影响，因此必须进行系统的研究以得到符合要求的制件。提出了相关工艺方法、模具设计关键技术。     

Spatially homogeneous gelation in liquid composite molding

On‐line mixing of the resin with its curing agents prior to injection into a mold is a common industrial technique for fabricating composite parts. For vinyl‐ester resins that cure via free radical polymerization, the concentrations of retarder, accelerator, and initiator are pre‐selected and cannot be changed during the injection. Hence, the resin that enters the mold the earliest has cured longer than the resin that enters the mold later, since the gel time for the resin is the same, owing to the fixed ratio of the curing agents. This approach leads to inhomogeneous cure of the resin and consequently to longer residence time of the resin in the mold. It requires an additional 50 to 75 percent of the filling time before a part can be de‐molded. In this study, it is shown that by adjusting the concentration of curing agents during the injection, a more homogeneous gel time throughout the mold can be achieved. The time to de‐mold is reduced to 18‐24 percent of the filling time. Sensors that measure the conductivity of the resin were used to detect the location and monitor the cure of vinyl‐ester. This approach could be extended to other resin systems to control the spatial curing of the resin in the mold.     

Use of sensors and actuators to address flow disturbances during the resin transfer molding process

In Resin Transfer Molding a fiber preform is placed in a mold, the mold is closed and a thermoset polymeric resin is injected through gates into the mold to saturate the preform completely. The resin flow rate is controlled by actuators, which are usually injection machines. When one places the preform into the mold, the gap between the preform and the mold walls can create race tracking channels and provide the resin flow paths that can severely influence the flow patterns and drastically change the flow history. As this gap is unavoidable and not reproducible, one could have different strengths of this disturbance from one part to the next, some of which will cause incomplete saturation of the fibers by the resin. Hence, an active control of the filling stage is necessary that can detect and characterize the race tracking and provide the control action to redirect the flow with the aim to saturate the preform without resin starved regions (macro voids or dry spots). A methodology is proposed that intelligently places sensors in the mold to detect the resin arrival times at these locations. This information is used to determine and quantify the strength of the disturbance and used as an input parameter for the actuators to redirect the flow. This paper demonstrates this methodology on a simple mold configuration, and outlines how this technique can be generalized to any mold geometry or disturbance set in an automated RTM environment. Numerical simulations are used to establish the control methodologies, and all of the efforts are confirmed in a laboratory setting. The proposed methodology should prove useful in increasing the yield of Resin Transfer Molded parts.     

Modeling nonisothermal impregnation of fibrous media with reactive polymer resin

The manufacture of polymer composites through resin transfer molding (RTM) or structural reaction injection molding (SRIM) involves the impregnation of a fibrous reinforcement in a mold cavity with a reactive polymer resin. The design of RTM and SRIM operations requires an understanding of the various parameters, such as materials properties, mold geometry, and mold filling conditions, that affect the resin impregnation process. Modeling provides a potential tool for analyzing the relationships among the important parameters. The present work provides the physical model and finite element formulations for simulating the mold filling stage. Resin flow through the fibers is modeled using two-dimensional Darcian flow. Simultaneous resin reaction and heat transfer among resin, mold walls, and fibers are considered in the model. The proposed technique emphasizes the use of the least squares finite element method to solve the convection dominated mass and energy equations for the resin. Excellent numerical stability of the proposed technique provides a powerful numerical method for the modeling of polymer processing systems characterized by convection dominated transport equations. Results from example numerical studies for SRIM of polyurethane/glass fiber composites were presented to illustrate the application of the proposed model and numerical scheme.     

Key factors affecting permeability measurement in the vacuum infusion molding process

The composites industry, under increased environmental constraints, is seeking to shift from existing open mold manufacturing processes for composite parts. A promising manufacturing technology known as the vacuum infusion molding process is gaining acceptance among composite-parts manufacturers since it involves low tooling cost and allows complete elimination of volatile organic compounds (VOC). The process is similar to the resin transfer molding process; however, in the vacuum infusion technique, a polymeric film, often referred to as vacuum bag, replaces the stiff mold cover. The film is sealed against the lower half of the mold, at the periphery. Air expelled from the mold cavity results in the compaction of the reinforcement by the atmospheric pressure present on the outer side of the polymeric film. Finally, resin impregnates the mold cavity, usually through a resin distribution channel. The process is mainly developed for large-scale structures, where material cost is an important parameter and users cannot afford any production pitfalls. Among process parameters that affect resin flow in the vacuum infusion molding process is the permeability of the reinforcement stack, which has to be measured and evaluated taking into consideration the requirements of the process. A possible approach is the definition of a parameter that defines the maximum infused length, and this parameter will take into account the structure of the reinforcement, the resin viscosity, the fiber volume fraction and inlet geometry.     

光学塑料注射模具的设计制作与制品的成型工艺

从模具结构设计,模具材料及热处理选择,模具成型零件的加工工艺,塑料材料及成型及工艺选择,生产环境诸方面的述了生产优质光学塑料制品的方法和影响光学塑料制品的因素。     

Failure mechanisms in stereolithography injection molding tooling

Stereolithography tooling is a form of rapid tooling that has been used to injection mold limited runs of prototype parts. However, the process is not well understood and tooling life for fine mold features is difficult to predict. Injection molding processing conditions and feature geometry affect the number of parts that can be made before a mold fails. To study the effects of feature geometry, general purpose polystyrene parts were injection molded in molds made of DSM Somos 7110 stereolithography resin. The ACES build style was used, and no polishing was performed on the mold. The experimental results were compared with theoretical models developed for the two failure mechanisms for raised features in a stereolithography mold—failures during injection due to the flow pressure of the injected polymer; and failures during ejection, whereby the part pulled out a feature of the mold. Injection failures occurred in taller mold features due to the force of flow and the feature's geometry. Ejection failures occurred in the shorter features when the stress from the ejection force (distributed over the bond area) exceeded the yield strength of the mold material. Models were developed to predict the number of parts that a mold could make before mold features break off and were validated through experimental results.