Effect of different initiators on temperature-sensitive monolithic columns and application in online enrichment of β-sitosterol

Three temperature-sensitive monolithic columns were prepared by atom transfer radical polymerization and oxidation–reduction method using the initiator systems of CCl₄/FeCl₂, BPO/DMA, and APS/TEMED, respectively. The three monoliths were characterized by scanning electron microscopy, nitrogen adsorption, and thermogravimetric analysis. The obtained monolithic columns were used as on-line solid phase extraction sorbent coupled with high-performance liquid chromatography for the enrichment of β-sitosterol. By comparing some influencing factors on the adsorption, the optimum temperature-sensitive monolithic column which was initiated by CCl₄/FeCl₂ was selected for enrichment of β-sitosterol from plant oil. The maximum adsorption capacity of the monolith for β-sitosterol was 10.0031 mg/g. The limit of detection and limit of quantitation were 0.039 and 0.13 mg/mL, respectively. The recovery was in the range of 90.21–98.26%. The results showed that the monolith had better selectivity for β-sitosterol and could be used for enrichment of β-sitosterol in food samples. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47683.     

温敏水凝胶的合成研究

以N—N亚甲基双丙烯酰胺为交联剂,以过硫酸钾一亚硫酸氢钠为引发剂,甲基丙烯酸-2（甲氨基）乙酯作为主要单体,与N-乙烯基吡略烷酮和衣康酸进行自由基水溶液共聚合,通过改变单体物质的量比及交联剂用量制备一系列温敏水凝胶。对制备的水凝胶结构通过红外进行表征,研究其对温度的敏感性行为。实验证明：随N-乙烯基吡咯烷酮和衣康酸比例的增大,凝胶的温敏区间（35—38℃）趋于稳定,凝胶的吸水膨胀率不断降低,凝胶吸水膨胀率下降程度增大;单体比例一定的条件下,凝胶的吸水膨胀率随温度升高而减小;交联剂用量对凝胶的温敏区间影响不大,随交联剂用量的增加吸水膨胀率先增大后减小,当交联剂用量为4．5‰时,吸水膨胀率达到最大。     

温度敏感葡聚糖凝胶的合成及其细胞相容性研究

合成了N-异丙基丙烯酰胺（NIPAAm）与葡聚糖的共聚水凝胶，利用红外光谱表征了单体和凝胶结构，研究了水凝胶在去离子水和细胞培养基中的温度响应性，并对凝胶进行了细胞培养和脱附研究．结果表明，共聚凝胶具有很好的温度敏感性和细胞相容性，可以通过控制温度变化，实现对细胞的无损伤脱附．     

Salt effect on the phase transition behavior of thermo-sensitive polyamide

Phase transition behavior and influence of ions on the thermo-sensitive polyamide with polyethylene glycol as the main chain were studied in detail.By measuring the light transmission rates of polymer solutions,the change of its lower critical solution temperature（LCST）in the salt solution was investigated.It was found that a reversible phase transition of the polyamide occurred at the LCST and fi nished in a narrow temperature range.The LCST was associated with species of ions in salt solution.Anions had a great impact on the phase transition performance of the thermo-sensitive polyamide,while the cations had a slight influence on the phase transition.Different anions had different coagulation ability to ’salt-out’ the polyamide.The order was:CO₃^2->SiO₃^2->HPO₄^2->OH^->Cl^->HCO³->HSO³->NO²->NO^3-.     

热采水平井新型套管热力补偿器

现有热采水平井套管补偿器开启压力若设置过大,套管会因补偿器开启不及时而损坏,若开启压力设置过小,又易在完井过程中提前开启。为此,开发了SCYRB型热力补偿器。该补偿器采用温敏式材料来做补偿器的开启装置,常温时补偿器处于锁死状态,管柱在轴向无法伸缩;当温度达到设定值时,补偿器为开启状态释放管柱,使补偿器两端管柱处于可以自由伸长状态,通过补偿管柱轴向伸长量的方式达到降低应力集中、保护管柱的目的。目前,该补偿器已推广应用40～50套,工作正常,尚未发生完井管柱破损事故,成功率达到100%。     

Preparation and characterization of a temperature-sensitive nonwoven poly (propylene) with antibacterial properties

In this study, a temperature-sensitive fabric with antibacterial properties was prepared by the formation of silver nanoparticles (AgNPs) on nonwoven poly (propylene) (PP) grafted with poly (N-iso-propylacrylamide) (PNIPAAm-PP). First, PNIPAAm was grafted onto corona-treated nonwoven PP. Afterwards, silver nanoparticles were synthesized on the temperature-sensitive hydrogel layer grafted to the surface of nonwoven PP by the reduction of silver ions (Ag⁺). Fourier transform infra-red spectroscopy confirmed the presence of PNIPAAm on the nonwoven PP. scanning electron microscopy-energy dispersive X-ray spectroscopy was used to investigate surface morphology and the presence of silver particles in the samples. Inductively coupled-plasma atomic emission spectroscopy revealed that the Ag content in Ag-functionalized PNIPAAm-PP was significantly higher than Ag-functionalized corona-treated PP with the same concentration of silver solution. Moreover, the results of the swelling rate experiment confirmed that PNIPAAm-PP maintained temperature-sensitive properties after functionalizing with Ag. The results showed that the formation of AgNPs with enhancement in antibacterial property was possible onto PNIPAAm-PP.     

苯并噻唑类离子液体在乳酸酯中的溶解度测定

为促进离子液体的应用,在常压下由平衡法测定了3种新型苯并噻唑类离子液体在乳酸甲酯、乳酸乙酯中的溶解度,温度范围为253.15～333.15 K,用λh方程对溶解度数据进行了关联,关联效果理想。该类离子液体表现出的"温敏性"对其在反应结束后的回收及循环使用具有重要意义。     

数控机床温度敏感点变动性及其影响

数控机床热误差补偿技术中的核心问题是建立能够反映机床温升与热误差之间的数学模型,其精度和稳健性则取决于模型自变量能否准确地反映机床温度场分布特性,即温度敏感点选择结果是否准确和稳定。通过对Leaderway-V450型数控加工中心主轴Z向的多批次空转数据进行分析发现,温度敏感点存在变动性特征,导致自变量间多重共线性程度发生变化,进而对模型的预测精度和稳健性产生严重影响。由于主成分回归算法具有消除自变量共线性影响作用,故提出采用该算法进行建模,并通过实际机床进行实践检验。结果表明,采用主成分回归算法建模,显著降低了温度敏感点变动性对模型预测精度的影响,能保证模型具有很好的预测精度和稳健性。     

基于全织物传感网络的温敏服装设计

为实现对人体皮肤温度的实时监测,在深入研究现有监测技术的基础上,结合人体不同部位皮肤温度分布存在差异,以及人们对温敏服装的可重复性及舒适性的要求,通过建立人体区域传感网络的阵列式排列模型与数据采集存储系统的设计方法,最终制备基于全织物传感网络的温敏服装。测试全织物温度传感网络的拉伸回复性,证明其具有较高的稳定性。测试温敏服装的温敏性并评估其可重复性和舒适性,证明其具有较高的灵敏度及良好的实用性。综合比较数据采集模块的实用性,最终开发出便携式数据采集存储系统。结合数据采集系统采用温敏服装实时监测人体皮肤温度,证明可通过人体温度的变化曲线追踪人体的呼吸状态,同时满足舒适性要求。