除氧装置在PA66切片干燥过程中的应用

分析了PA66切片氮气干燥系统含氧量偏高的原因,说明了安装除氧装置的必要性。应用表明,在原有系统上安装以钯触媒为催化剂并适量加氢与氧反应的除氧装置,控制加氢量2％-3％,干燥系统的含氧量由原来的50μg／g降低到5μg／g以下．有效的防止了PA66切片的氧化,保证了PA66纺丝和后加工过程的稳定,提高了产品质量。     

The effect of active azodyes on the polycaproamide photo-oxidation kinetics

Investigations were carried out on polycaproamide films(PCA) at room temperature in air. Samples were dyed with oxyethylsulfonic and monochlortriasinic active dyes. Irradiation was carried out with a low-pressure Hg lamp (λ = 254 nm, intensity equals 1.5 × 10¹⁵ sm^?2 sec^?1). During irradiation, ESR spectra of five poorly resolved lines of superfine structure were observed for all samples. Analysis of ESR spectra shows that quintet belongs to radicals $ \sim {\rm CONH\dot CHCH}_{\rm 2} \sim $. The initial accumulation rate of radicals was measured on linear parts of radical accumulation curves. Similarly, accumulation of PCA carboxyl groups kinetics was measured. The initial accumulation rates of radicals and carboxyl groups are linear functions of absorbed radiation on polymer and dye. There is a tendency of increasing carboxyl group yields with radical yields for different dyes. One can assume that it follows from this correlation that radicals are precursors of carboxyl groups. Luminescence spectra measured for PCA with salt and covalent bonded dyes are located near 425 nm. The data allow the conjecture that PCA luminescence is connected with centers bonded with PCA macromolecules.     

Optical and mechanical properties of cocona chips as affected by the drying process

The effect of the application of a pre-osmotic treatment to obtain hot air dried cocona (Solanum sessiliofurum Dunal) chips was studied. The drying kinetics and the optical and mechanical properties of cocona chips obtained by the combined method of osmotic dehydration and hot air drying (OD + HAD) and by only hot air drying (HAD) were compared. Samples were dried by hot air at 60 °C. For the combined method, they were pre-dried to a moisture content of 75 g_water/100 g, immersed in a 55 °Brix sucrose solution at 25 °C for 48 min. The pre-osmodehydration applied did not influence the subsequent hot air drying kinetics, resulting in a final product with 0.055 ± 0.005 g_water/g_cocona. The optical properties of OD + HAD chips were more favorable, exhibiting a smaller color change with respect to the fresh fruit (±15 units) than the HAD samples (±23 units). On the other hand, the OD + HAD chips presented more fracture peaks than HAD ones, this related with a structure with a higher degree of crispness, a very desirable property for a chip product.     

褐煤等温干燥过程及动力学研究

为研究褐煤干燥过程,利用煤质水分分析仪和微分热重分析方法,对不同粒级的褐煤在不同干燥温度下进行等温干燥试验,得到了样品含水率与干燥时间、干燥速率与含水率的关系曲线。通过粒级分布系数对褐煤进行含水率折算,并用不同干燥模型对试验数据进行拟合,得到了在介质温度140℃下3个干燥阶段的干燥方程及干燥动力学参数。结果表明,引入粒级分布系数得到的干燥速率特征常数k值,与不同粒级的干燥速率特征常数k的均值相近。根据褐煤的干燥速率和水分的存在形式,将褐煤干燥过程分为3个干燥阶段,分析得出干燥方程模型分别用线性干燥模型、Wang经验模型、Page模型较为合理。根据Arrhenius经验公式建立了ln k与1/T的关系,得到褐煤干燥的界面蒸发活化能Ea=17.088 k J/mol,指前因子A=12.47 min~(-1)。     

Optimization of the microwave drying process for potato chips based on the measurement of dielectric properties

A microwave drying system with functions of automatic power and temperature control was developed to dry potato chips. The mass and moisture content of the sample are available online. The dielectric properties of the samples were measured during microwave drying, during which the microwave absorption capacity of the samples was analyzed. Afterward, a reasonable power and temperature control scheme was formulated. The enhanced microwave drying technology of potato chips is found by comparing product quality under different schemes. Results show that the change in the dielectric properties of materials during microwave drying is closely related to moisture and temperature variations. A three-stage different temperature control with predefined variable power profiles resulted in the best product quality.     

Combining the process of heat-setting and rewinding polycaproamide yarns

Conclusions The fundamental possibility of preparing heat-set polycaproamide yarns of 4 tex linear density which conform to the requirements of technical conditions has been demonstrated.Heat-set yarns which have been prepared with combination of the heat-setting and rewinding processes have a more uniform shrinkage by package layers than when they are treated with hot water or steam on rigid packages.Combining the processes of heat-setting and rewinding will make it possible to shorten the technological process of manufacturing textile polycaproamide yarns.Translated from Khimicheskie Volokna, No. 3, pp. 43–44, May–June, 1988.     

Intensifying graft-polymerization in the process of modifying polycaproamide fibres

Conclusions -- The kinetics of the graft polymerization of dimethylaminoethyl methacrylate to polycaproamide fibre initiated by the redox systems Fe²⁺ - H₂O₂, Cu²⁺ - H₂O₂, and by an ROC containing a complex copper compound (Cu _c ²⁺ - H₂O₂) has been studied.-- An increase in the rate of graft polymerization, in the amount of grafted component, and the degree of useful conversion of the monomer has been found when the reaction is initiated by the ROS Cu _c ²⁺ - H₂O₂.Moscow Textile Academy. Translated from Khimicheskie Volokna, No. 3, pp. 11–12, May–June, 1992.     

陶瓷坯体干燥过程控制

在陶瓷坯体干燥过程中,坯体在干燥器内的运动控制相当关键。采用单片机对坯体干燥运动过程进行实时准确的控制,使干燥过程有序地进行,从而提高生产率和产品质量。     

胶乳法氯化天然橡胶干燥历程中脱氯化氢反应动力学

新型工艺胶乳法氯化天然橡胶(CNR)产品在干燥过程中会有HCl脱出,其脱出量对CNR的制备、性能等有一定的影响。采用电导法可连续测定CNR在干燥历程中脱HCl量及速率,这是研究CNR在低温下热降解行为的有效方法。用改进工艺的"胶乳法"制备出湿的CNR,并在一定温度下通入氮气进行干燥,在此历程中会发生脱氯化氢反应,其反应过程可分为诱导期、恒速期和低速期。文中使用Friedman法分析该过程在恒速期、低速期的反应动力学参数,其脱氯化氢反应分别为0级反应、1级反应,活化能分别为26.65,36.79 kJ/mol。在80℃以下对产品进行加热(或干燥),虽有少量HCl脱出,但并不会对产品质量造成影响。所以干燥温度应以低于80℃为宜。     

Change in properties of polycaproamide during a heat-treatment process

Conclusions -- The change in basic molecular and certain specific characteristics of PCA during the process of heat-treating it in the presence of air has been studied.-- It has been shown that the degree of thermo-oxidative degradation of PCA may be judged from the change in molecular weight characteristics in combination with the results of change in the Huggins constant, the relative chemical nonuniformity, the content of carbonyl compounds, and the integral UV-absorption.-- The inhibiting action of a Bulgarian copper thermostabilizer and of N-1 thermostabilizer on the thermo-oxidative degradation of PCA has been evaluated.Translated from Khimicheskie Volokna, No. 6, pp. 42–44, November–December, 1990.     

A continuous technological line for the extraction and drying of NéS-KS-5 polycaproamide

Conclusions The quality of PCA granulate obtained on the continuous line of the NÉS-KS-5 machine (man-made yarn combine, Vidin, Bulgaria) has been analyzed.Experimental specimens of the yarns prepared from this granulate have better processibility in the textile treatment process, which makes it possible to reduce the amount of technological waste by a factor of 2.6.Bulgaria. Translated from Khimicheskie Volokna, No. 1, pp. 41–42, January–February, 1984.     

氯气干燥工艺流程选择

简述了氯气干燥原理及几种典型的氯气干燥工艺流程(串联的填料塔组流程、强化型泡沫塔流程及填料塔与泡罩塔组合流程).提出干燥塔组合流程要降低氯气中水分,关键是严格控制进塔氯气冷却温度、出塔硫酸浓度、进塔硫酸浓度和温度以及出塔氯气温度等工艺参数,同时选用效率较高的除雾过滤技术.     

A study of the high-speed spinning process for polycaproamide complex yarns

Conclusions -- The basic laws governing the effect of spinning conditions on the properties of PCA yarns have been investigated. It has been shown that in distinction to spinning monofilaments, in high-speed spinning of complex yarns, additional factors appear by use of which it is possible to effectively control the properties of the yarns obtained.-- It has been found that the site of disposition of the aqueous lubricant in the high-speed spinning PCA yarns exerts a fundamentally different action on the breaking elongation of the yarns and on their structure, depending on the linear density and the number of elementary filaments in the complex yarn; however, it does not change the character of this dependence on the breaking strength of the yarn.-- Under otherwise equal conditions, a lower disposition of the lower lubricating device helps in obtaining complex PCA yarns which have a larger breaking strength and a lower elongation.Translated from Khimicheskie Volokna, No. 1, pp. 19–21, January–February, 1991.