Bead Coating Process Via an Excess of Crosslinking Agent

Coated beads were prepared by soaking in sodium alginate solutions spherical matrices (beads) of carboxymethylcellulose crosslinked with aluminum chloride (AlCl3) and loaded with ambroxol hydrochloride as a model drug. The residual amount of the crosslinker induced an interfacial crosslinking reaction of the sodium alginate. Therefore, an insoluble, smooth and uniform in thickness coat was formed around the beads. As the coating time increased, the coat thickness increased until1 AlCl3 was present inside the beads. The rate of drug release from the coated beads was slower than that from the uncoated beads and decreased with the increase in coating time. Moreover, a constant rate phase, subsequent a burst period for the samples obtained with the highest coating times, was achieved. The dynamic swelling analysis allowed to exclude the influence of the polymer relaxation on the release process which appeared to be controlled by the alginate coat.     

用谷氨酸为交联剂制备玉米交联氧化淀粉胶黏剂及性能研究

目的 改善淀粉胶黏剂胶合强度低、耐水性差等缺点,通过对玉米淀粉(CS)进行改性,制备玉米交联氧化淀粉胶黏剂(CCOSA)。方法 以CS为主要原料,以生物质材料谷氨酸为交联剂,以过氧化氢为氧化剂,采用先交联后氧化的方法制备CCOSA。通过单因素试验确定制备玉米交联淀粉(CCS)和玉米交联氧化淀粉(CCOS)的最优条件,通过FT-IR对制备的CCS 和CCOS进行结构表征,并测定制备的CCOSA的基本理化性能、耐水时间和胶合强度。结果 得到了制备CCS的优化工艺条件,当CS的质量为20 g、谷氨酸的质量为1.0 g、pH为9、反应温度为55 ℃、反应时间为1.5 h时,制得的CCS的沉降积(0.55 mL)最小、交联度最大。得到了制备CCOS的优化工艺条件,在CCS的质量为20 g、FeSO4的用量为CCS质量的0.1%、质量分数为30%过氧化氢的用量(体积)为2 mL、反应温度为50 ℃、pH为3、反应时间为3 h时,制得的CCOS的羧基含量为0.184%,对CCS的氧化效果最好。通过FT-IR分析可知,CCS在1 157.22 cm⁻¹处出现了C—N伸缩振动吸收峰,CCOS在1 731.35 cm⁻¹处出现了C=O伸缩振动吸收峰,此吸收峰向高波数移动,而且此峰相对于1 653.25 cm⁻¹典型的淀粉衍生物C=O吸收峰的强度明显增强。在此条件下制得的CCOSA的胶合强度为6.15 MPa,比玉米交联淀粉胶黏剂(CCSA)、玉米氧化淀粉胶黏剂(COSA)和未改性玉米淀粉胶黏剂(CSA)的胶合强度分别提高了38.83%、107.07%、352.21%,并且CCOSA的耐水性得到明显提高。结论 FT-TR分析结果表明,采用先交联后氧化的方法成功制得了CCOS,制得的CCOSA的胶合强度和耐水性得到明显提高。     

LED封装用液体交联剂的制备与表征

报道了一种功率型发光二极管(LED)封装用液体高分子交联剂的制备方法。将甲基氢环硅氧烷与八甲基环四硅氧烷、甲基苯基混合环体等环硅氧烷,在甲苯溶剂中,40℃~80℃,用阳离子交换树脂催化其开环共聚,并以适量四甲基二氢硅氧烷封端。产物为澄清透明的甲基苯基含氢硅油,其苯基含量(Ph/Si,molar ratio)为0.30~0.60,活泼氢(Si-H)含量为0~0.5%,折光指数为1.39~1.51(25℃),动力黏度为100 mPa.s~550 mPa.s(25℃)。     

Analysis of Discontinuous Bead Formation by PTAW Process

This research investigates the effects of input parameters on discontinuities in bead formation during material deposition by the plasma transferred arc welding (PTAW) process. Experiments based on L27 orthogonal array have been carried out by deposition of stainless steel powder (SS304 L) on stainless steel plate (SS316). Three types of depositions have been observed, namely continuous, partially continuous and discontinuous deposition. A process map has been developed, based upon powder and energy deposition per length, where the above-mentioned three types of depositions are distributed. The discontinuities in the deposition can be overcome by increasing the energy deposition per length or by reducing the powder deposition per length.     

阳离子聚丙烯酰胺基复合增强剂对瓦楞原纸增强作用研究

目的探讨CPAM-HPCS-PAE复合增强剂作为增干、湿强剂在瓦楞原纸中的应用效果,并与CPAM增强剂和CPAM/HPCS/PAE混合物比较增强效果。方法将羟丙基壳聚糖(HPCS)、CPAM及PAE树脂通过交联反应制得CPAM-HPCS-PAE复合增强剂。结果 CPAM-HPCS-PAE复合增强剂质量分数为0.5%时,纸张具有较好的机械强度,与单独使用CPAM增强剂和CPAM/HPCS/PAE混合物相比,该复合增强剂不但能明显提高瓦楞原纸的干强性能,而且还能显著改善其湿强性能。SEM及光散射系数检测结果表明,CPAM-HPCS-PAE复合增强剂的加入能够显著改善纸张纤维之间的交织,增加纤维之间的结合面积,从而对纸张起到增强作用。结论 CPAM-HPCS-PAE复合增强剂不但具有良好的增干强性能,而且具有一定的增湿强性能。     

马铃薯废渣复合涂膜剂保鲜性能研究

目的以马铃薯废渣为原料,制取复合涂膜剂对苹果进行保鲜,研究马铃薯废渣的新用途。方法以马铃薯废渣为原料,通过溶媒法制取羧甲基纤维素,将羧甲基纤维素与壳聚糖、纳米Si Ox混合制得涂膜剂,对苹果进行涂膜保鲜;通过正交实验优化实验方案,确定富士苹果最佳保鲜处理方案。结果保鲜效果最佳的复合涂膜剂配方为羧甲基纤维素、壳聚糖、纳米Si Ox和丙三醇的质量分数分别为0.5%,1.5%,0.1%和0.75%。复合涂膜剂有效抑制了苹果的呼吸作用,延缓了果实的衰老,降低了果实的失重率,减缓了有机酸的消耗,抑制了果实硬度的下降和病菌对苹果的侵染。结论实验研究结果拓展了马铃薯废渣的用途,为马铃薯废渣处理提供了借鉴。     

交联剂对PVP/PCL共聚凝胶性能的影响

研究了N,N-亚甲基双丙烯酰胺(NMBA)、戊二醛(GDA)两种交联剂对聚乙烯吡咯烷酮(PVP)/聚己内酯(PCL)共聚水凝胶性能的影响。交联剂含量低于NVP的0.7%时,GDA交联凝胶平衡溶胀率ESR较高,高于0.7%时,NMBA交联凝胶的ESR较高。DSC分析表明,GDA交联凝胶结合水含量较高。NMBA、GDA交联凝胶的Fick动力学参数n分别为0.462、0.267,说明GDA交联凝胶的溶胀过程偏离Fick模型。降解实验表明,GDA交联凝胶中PCL降解较慢。力学性能测试表明,GDA交联凝胶表现出较高的断裂强度和断裂伸长率。     

降低冰柜磷化药剂耗量的方法

探讨了降低冰柜磷化药剂消耗的几种对涂装质量的影响,将磷化柄液浓度至总酸度１０－１５点,游离酸度０．４－０．７点,即可保证涂装质量,以能减少磷化药剂消耗约２０％,产品质量和经济两全齐美。     

新型自泳涂料后处理剂及工艺的研究

自泳涂料是一种新型的特殊乳胶涂料,使用时不仅涂装工艺简单、涂层均匀、不存在泳透力问题,而且具有成本低、无污染等特点,正在逐步推广应用于各个领域.针对目前自泳涂料多采用含铬后处理剂,不利于环境保护的缺陷,制得一种新型自泳涂料后处理剂,并通过试验研究了其配套性能的一系列影响因素,确定其使用工艺.根据自泳涂膜的各项性能测试结果表明,使用该后处理剂的漆膜外观平整,附着力优良,适用于自泳涂料的钝化处理.     

Bead Coating: II. Effect of Spheronization Technique on Drug Release from Coated Spheres

The effect of spheronization method on drug release from coated spheres may be evaluated by determining the drug release rate, the critical coating level and the release mechanism. Drug release is faster from pan beads than from marumerizer beads at the same coating level. An equation is proposed which indicates that the critical coating level is inversely proportional to sphere size and sphere density, which in turn results from the different spheronization techniques. From the calculation, the critical coating levels for 14/16 mesh cuts of marumerizer beads and pan beads are 12% and 18%, respectively. Disintegration, pore-control and barrier control are involved in the release mechanisms of drugs from coated pan beads.     

乙烯-乙烯醇基大分子型强化交联剂的合成与应用

通过酯化反应制备了乙烯-乙烯醇.丙烯酸(EVOH-AA)接枝型材料,并用红外光谱对接枝产物进行了袁征.凝胶抽提结果表明,由于乙烯基双键的引入,难于辐射交联的EVOH在较低的辐射剂量下就可以辐射交联.具备成为强化交联剂的可能.通过研究改性EVOH与聚乳酸共混物的辐射效应,发现聚乳酸进入交联网格,证明改性EV0H具有一定的...     

Bead Coating: II. Effect of Spheronization Technique on Drug Release from Coated Spheres

Abstract

The effect of spheronization method on drug release from coated spheres may be evaluated by determining the drug release rate, the critical coating level and the release mechanism. Drug release is faster from pan beads than from marumerizer beads at the same coating level. An equation is proposed which indicates that the critical coating level is inversely proportional to sphere size and sphere density, which in turn results from the different spheronization techniques. From the calculation, the critical coating levels for 14/16 mesh cuts of marumerizer beads and pan beads are 12% and 18%, respectively. Disintegration, pore-control and barrier control are involved in the release mechanisms of drugs from coated pan beads.     

镍铁钨合金电沉积工艺

为获得性能良好的镍铁钨合金镀层,研究了电解液pH值、温度、电流密度、柠檬酸钠浓度对施镀阴极电流效率和镍铁钨合金镀层组分、表面形貌、显微硬度的影响.结果表明:镀液pH值对镀层形貌和阴极电流效率影响较大;随柠檬酸钠浓度增加,电流效率逐渐降低,镀层表面形貌更加粗糙.在镀液pH=8,温度70℃,电流密度7 A/dm2,柠檬酸钠...     

饱和聚酯辊涂工艺参数对涂层性能的影响

目的为了提高金属罐漆膜质量,研究不同辊涂工艺参数对金属罐外涂膜性能的影响。方法探讨在饱和聚酯辊涂过程中的涂料黏度,取料辊与涂覆辊间距,芯轴速度与滚筒速度(周速比)等工艺参数对涂层性能影响,从而得出金属罐最佳辊涂工艺参数的设置范围。结果涂料黏度,取料辊与涂覆辊间距,芯轴速度与滚筒速度(周速比)等工艺参数对金属罐漆膜的附着力、硬度、耐热性均有影响。结论当涂料黏度为85 s(DIN6黏度杯),取料辊与涂覆辊间距为-4μm,芯轴速度与胶辊速度(周速比)为2∶1时,漆膜的综合性能最好。     

含Ag-Zn无机抗菌剂的Ca3(PO4)2涂层的抗菌性能

采用等离子喷涂方法在OCr18Ni9Ti不锈钢基体上制作分别含有不同含量Ag-zn无机抗菌剂的涂层.X射线衍射(XRD)测试分析表明:涂层中的Ag-Zn无机抗菌剂为ZnO2、Ag2O2和Ag2SO4;涂层对大肠杆菌ATCC 8099和金黄色葡萄球菌ATCC 6538的抗菌性能表明:含Ag-Zn无机抗菌剂的磷酸钙涂层具有优异的抗菌性能,随涂层中Ag-Zn无机抗菌剂含量的增加和涂层与细菌作用时间的延长,涂层的抗菌率提高.     

Regulating Drug Release Via Non-Uniform Distribution of Coating Composition in Multilayer Drug-Coated Granules

Multilayer drug-coated granules with a non-uniform distribution of the coating composition specifically the drug loading and the polymer viscosity, across the thickness of the film matrix were prepared by the fluidized bed coating process. The rate and duration of diphenhydramine hydrochloride release from the coated granules can be modified through control of the gradient change in the coating composition across the thickness of the methylcellulose (MC) film matrix. A steeper gradient change across the film matrix resulted in a slower overall release rate. Formulations with gradient drug loading distribution exhibited an extended release time that can be twice as long as that for the control formulation. Gradient layered matrices obtained by sequentially depositing different viscosity grades of MC produced release profiles that differed from film matrices prepared using MC blends.     

Regulating Drug Release Via Non-Uniform Distribution of Coating Composition in Multilayer Drug-Coated Granules

Multilayer drug-coated granules with a non-uniform distribution of the coating composition specifically the drug loading and the polymer viscosity, across the thickness of the film matrix were prepared by the fluidized bed coating process. The rate and duration of diphenhydramine hydrochloride release from the coated granules can be modified through control of the gradient change in the coating composition across the thickness of the methylcellulose (MC) film matrix. A steeper gradient change across the film matrix resulted in a slower overall release rate. Formulations with gradient drug loading distribution exhibited an extended release time that can be twice as long as that for the control formulation. Gradient layered matrices obtained by sequentially depositing different viscosity grades of MC produced release profiles that differed from film matrices prepared using MC blends.     

大分子引发剂和交联剂对PDLC电光性能的影响

采用反向原子转移自由基聚合制备苯乙烯引转移终止剂活性大分子(MI),并通过光聚合诱导相分离法制备聚合物分散液晶(PDLC)膜,研究了MI含量和交联剂(HDDA)的含量对PDLC开态透光率、阈值电压(Vth)、饱和电压(Vsat)、记忆效应和对比度的影响。结果表明,当PDLC中的MI含量从5%增到10%时,开态透光率增加,而阈值电压(Vth)、饱和电压(Vsat)降低,记忆效应增强,对比度先增加,然后又降低;当PDLC中的HDDA含量从25%增加到90%时,开态透光率降低,Vth、Vsat增加,记忆效应减弱。