邻苯二酰化壳聚糖与聚乳酸接枝共聚物的研究

选用三种不同分子量的壳聚糖进行实验,对接枝共聚物的制备的工艺及条件进行较为详细的研究.采用"保护氨基-接枝反应-脱保护"的接枝路线,将聚左旋乳酸接枝在不同分子量的壳聚糖主链上,制得壳聚糖接枝聚乳酸共聚物.结果表明:(1)通过改变投料比、温度、时间等条件确定最佳的工艺条件制备邻苯二甲酰化壳聚糖(PHCS).在投料比(CS...     

聚乳酸接枝改性壳聚糖性能

以二甲基亚砜(DMSO)为反应介质,辛酸亚锡(C16H30O4Sn)为催化剂,研究了壳聚糖(CS)与D-丙交酯(DLA)在非均相条件下的接枝反应,得到D-丙交酯与壳聚糖接枝共聚物(CS-g-PDLA)。分析了反应温度、丙交酯与壳聚糖的投料比、反应时间对接枝率的影响。并利用红外变化光谱、X射线衍射、热重分析等对接枝共聚物进行了表征。实验结果表明,在DMSO中,当辛酸亚锡用量为丙交酯投入质量的0. 05%时,随着丙交酯投入比的增加,接枝率呈现明显上升的趋势;随着反应温度与反应时间的增加,接枝率呈现先增大后减小的趋势,即当反应温度为100℃、丙交酯与壳聚糖投料比为4∶1、反应时间为18 h时,D-丙交酯与壳聚糖接枝共聚物的接枝率最高,为82%。     

壳聚糖与丙烯酰胺接枝共聚物的制备及其性能研究

采用接枝共聚法,以K2S2O8-NaHSO3氧化还原引发体系为引发剂,使壳聚糖与丙烯酰胺进行自由基接枝共聚反应合成了壳聚糖-丙烯酰胺接枝共聚物。研究了K2S2O8的浓度、NaHSO3的浓度、壳聚糖与丙烯酰胺的质量比、反应温度、反应时间等因素对接枝率和接枝效率的影响。最适宜的反应条件是:c(K2S2O8)=3.0mmol/L,c(NaHSO3)=2.0mmol/L,m(壳聚糖)∶m(丙烯酰胺)=1∶5,反应温度50℃,反应时间3.5h。用FTIR表征壳聚糖-丙烯酰胺接枝共聚物的结构,同时试验了该接枝共聚物的絮凝性能。结果表明,该接枝共聚物的絮凝效果优于壳聚糖。     

壳聚糖/N-乙烯基吡咯烷酮接枝共聚物的制备及其性能

以壳聚糖（CS）和N-乙烯基吡咯烷酮（NVP）为原料,本文采用过氧化氢和抗坏血酸共引发剂引发,制备壳聚糖/N-乙烯基吡咯烷酮的接枝共聚物（CS-g-NVP）,研究了引发剂配比、反应温度和反应时间等因素对接枝共聚反应的影响。通过红外光谱、核磁共振和热重分析等对产物进行表征,并考察其吸湿性和亲水性能。结果表明,接枝共聚反应的最佳条件为：引发剂抗坏血酸/过氧化氢的摩尔比为1∶1、反应温度60℃、反应时间12h。接枝共聚产物的吸湿性优于壳聚糖,在饱和氯化钙和饱和硫酸铵环境下产物的吸湿率分别为3.68%和23.1%,高于原料壳聚糖的0.41%和9.77%,产物具有良好的亲水性和水溶性,能溶解于酸性和碱性水溶液中。     

紫外辐照引发PF-g-SAN接枝共聚反应的研究

以二苯甲酮（BP）为引发剂,通过紫外光辐照引发苯乙烯（St）、丙烯腈（AN）在纸浆纤维（PF）表面共聚,生成苯乙烯/丙烯腈共聚物（SAN）并接枝PF生成SAN接枝纸浆纤维（PE-g-SAN）,研究了引发剂BP浓度、St/AN质量比、辐照时间、反应温度对PF-g-SAN的接枝率和接枝效率的影响,用红外光谱仪和扫描电子电镜表征接枝产物,得出最佳反应条件为St/AN质量比2∶1,BP浓度2%,反应时间20 min,反应温度40℃。     

CR／MMA／VAc三元接枝胶粘剂的研制

探讨了氯丁橡胶（ＣＲ）、甲基丙烯酸甲酯（ＭＭＡ）、醋酸乙烯酯（ＶＡｃ）三元接枝共聚制备胶粘剂中ＭＭＡ与ＶＡｃ投料比、投料方式、反应温度、经发剂并添加促进剂Ａ对接枝反应及胶粘剂性能的影响，提出了制备配方和工艺条件。     

微波辐射下壳聚糖-丙烯酰胺接枝物的合成及其絮凝性能研究

以硝酸铈铵作为引发剂、丙烯酰胺为单体,用微波辐射法合成了壳聚糖-丙烯酰胺接枝共聚物。通过正交试验考察反应条件对接枝率和接枝效率的影响,得出最佳工艺条件为:反应时间12 min,引发剂浓度5 mmol/L,丙烯酰胺和壳聚糖质量比5:1,反应温度40℃。最佳条件下接枝率和接枝效率分别达到148.6%和44.0%。壳聚糖接枝物与聚丙烯酰胺(PAM)对高岭土悬浮液的絮凝对比试验表明:在酸性条件下接枝物与PAM的絮凝效果相近;在中性和碱性条件下接枝物的絮凝性能优于PAM。     

淀粉接枝甲基丙烯酸缩水甘油酯共聚物的合成与表征

以木薯淀粉为原料、过硫酸钾为引发剂,通过乳液聚合法制备淀粉甲基丙烯酸缩水甘油酯(GMA)接枝共聚物,系统考察了反应条件对接枝共聚物接枝率(G)、接枝效率(GE)以及环氧值(EV)的影响,并通过TG-DSC对接枝共聚物结构进行了表征。结果表明:在m(GMA)∶m(淀粉)=2,过硫酸钾浓度为6mmol/L,反应温度60℃,反应时间1h的条件下,可制得接枝率、接枝效率以及环氧值分别为:64.95%、95.57%、4.24mmol/g的接枝共聚物;接枝共聚物热稳定性比原淀粉有所提高。     

淀粉接枝丙烯酰氧乙基三甲基氯化铵共聚物的合成

以玉米淀粉为原料,在水介质中通过硝酸铈铵引发淀粉与丙烯酰氧乙基三甲基氯化铵(DAC)接枝共聚,制备系列含阳离子季铵基团的淀粉-DAC接枝共聚物,系统考察了反应条件对接枝共聚物接枝率(PG)的影响。结果表明:在本实验体系内可制备较高接枝率的阳离子接枝共聚物。当硝酸铈铵的浓度为1.5×10-2mol/L,m(DAC)∶m(淀粉)=3,反应温度40℃,反应时间4 h时,接枝共聚物的接枝率最高可达118.67%。用FTIR、1HNMR、XRD对接枝共聚物结构进行了表征。     

响应面法优化壳聚糖接枝工艺

利用响应面分析法优化壳聚糖接枝产物P的合成工艺,在以引发剂用量、原料质量比、反应温度为影响因素,以P(CTS/AM)接枝率为指标的单因素试验基础上,设计了三因素三水平的试验分析法,得到P最佳合成工艺条件:引发剂用量0.04g、m(CTS):m(AM)为 1∶2.8、反应温度为60℃.此条件下,P的接枝率为137.76％...     

稀土固体超强酸SO_4~(2-)/TiO_2/La~(3+)催化合成邻苯二甲酸二(2-乙基)己酯

以稀土固体超强酸SO42-/TiO2/La3+为催化剂,邻苯二甲酸酐和2 乙基己醇为原料,合成邻苯二甲酸二(2 乙基)己酯,考察了影响反应的因素。结果表明,醇∶苯酐(质量比)=2.5∶1,催化剂用量为苯酐的5%,反应时间2 5h时,酯化率可达92.7%。     

离子液体催化合成2-(4-乙基苯甲酰基)苯甲酸

研究了离子液体催化合成2-(4-乙基苯甲酰基)苯甲酸。并对离子液体中[Bmim]Cl与三氯化铝的摩尔比、原料配比、反应温度和反应时间等工艺条件进行了考察。较优工艺条件为:n(AlCl3)∶n([Bmim]Cl)=1∶3,n(离子液体)∶n(邻苯二甲酸酐)∶n(乙苯)=1∶1∶1,反应温度为50℃,反应时间为4h,在此条件下,[Bmim]Cl-AlCl3催化邻苯二甲酸酐的转化率可达100%,目标产物2-(4-乙基苯甲酰基)苯甲酸的选择性达97.14%,可避免使用有机溶剂。     

A study on cytocompatible poly(chitosan-g-l-lactic acid)

A novel cytocompatible graft copolymer of chitosan and l-lactic acid (CL) was prepared by grafting l-lactic acid onto the amino groups in chitosan without a catalyst. The structures of the CL graft copolymers were characterized by FTIR, ¹³C-NMR and X-ray measurements. Degree of substitution and side-chain length were evaluated from salicylaldehyde and elemental analysis. The tensile strength and water uptake of the CL copolymers films were investigated as a function of feed ratio of LA/CS. The influence of pH on the swelling behavior of the copolymer films was determined and interpreted. Fibroblast culture was performed to evaluate cell proliferation on the copolymers films. The results showed that the cell growth rate on the copolymers films is faster than chitosan obviously.     

Novel bioresorbable hydrogels prepared from chitosan‐graft‐polylactide copolymers

A series of biodegradable chitosan‐graft‐polylactide (CS‐g‐PLA) copolymers were prepared by grafting of poly(L ‐lactide) (PLLA) or poly(D ‐lactide) (PDLA) precursor to the backbone of chitosan using N,N′‐carbonyldiimidazole as coupling agent. The composition of the copolymers was varied by adjusting the chain length of PLA as well as the ratio of chitosan to PLA. The copolymers synthesized via this ‘graft‐onto’ method present interesting properties as shown by NMR and infrared spectroscopy, gel permeation chromatography and solubility tests. Hydrogels were prepared by mixing water‐soluble CS‐g‐PLLA and CS‐g‐PDLA solutions. Gelation was assigned to stereocomplexation between PLLA and PDLA blocks as evidenced by differential scanning calorimetry and wide‐angle X‐ray diffraction measurements. Thymopentin (TP5) was taken as a model drug to evaluate the potential of these CS‐g‐PLA hydrogels as drug carriers. An initial burst and a final release up to 82% of TP5 were observed from high‐performance liquid chromatography analysis. Copyright © 2011 Society of Chemical Industry     

Preparation and characterization of chitosan‐graft‐poly(L‐lactic acid) microparticles

To improve the properties of chitosan (CS) and poly(L‐lactic acid) (PLLA) and obtain fully biodegradable materials, CS‐g‐PLLA copolymers were prepared using 1‐(3‐Dimethylaminopropyl)‐3‐ethylcarbodiimide hydrochloride (EDC)/N‐hydroxyl succinimide (NHS) as a coupling agent. The copolymers were characterized by Fourier transform infrared analysis (FTIR), ¹H nuclear magnetic resonance (¹H NMR), elemental analysis, differential scanning calorimetry (DSC), X‐ray diffraction (XRD) and scanning electron microscopy (SEM). The results obtained by FTIR and ¹H NMR showed that CS and PLLA were grafted successfully via an amide bond. DSC and XRD results showed that the thermal stability of CS had been significantly improved by grafting PLLA to the molecular chains of CS and the crystallinity of the CS‐g‐PLLA copolymers decreased significantly. Elemental analysis showed that the achieved the maximum degree of substitution of PLLA was 60.88%, while the concentration of CS was 2 mg/mL, the PLLA molecular weight was 10,000, and the EDC/NHS ratio was 2:1. Images from SEM demonstrated that the copolymers had a spherical shape and smooth surface. Moreover, the products were well dispersed without any aggregation. POLYM. ENG. SCI., 56:1432–1436, 2016. © 2016 Society of Plastics Engineers     

Fabrication and in vitro investigation of nanohydroxyapatite,chitosan, poly(L‐lactic acid) ternary biocomposite

The nanohydroxyapatite/chitosan/poly(L ‐lactic acid) (HA/CS/PLLA) ternary biocomposites were prepared by blending the hydroxyapatite/chitosan (HA/CS) nanocomposites with poly(L ‐lactic acid) (PLLA) solution. Surface modification by grafting D ‐, L ‐lactic acid onto the HA/CS nanocomposites was designed to improve the bonding with PLLA. The FTIR and ¹³C‐NMR spectrum confirmed that the oligo(lactic acid) was successfully grafted onto the HA/CS nanocomposites, and the time‐dependent phase monitoring showed that the grafted copolymers were stable. The TEM morphology of the HA/CS/PLLA ternary nanocomposites showed that nano‐HA fibers were distributed homogeneously, compacted closely and wrapped tightly by the CS and PLLA matrix. The ternary biocomposites with the HA content of 60 and 67 wt % exhibited high compressive strength of about 160 MPa and suitable hydrophilicity. The in vitro tests exhibited that the ternary biocomposites have good biodegradability and bioactivity when immersed in SBF solutions. All the results suggested that the n‐HA/CS/PLLA ternary biocomposites are appropriate to application as bone substitute in bone tissue engineering. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

聚氨酯型不饱和聚酯涂料的研究

通过对反应过程中和涂膜酸值和粘度测定以及涂膜性能测定和红外光谱分析研究了聚氨酯型不饱和聚酯树脂的反应温度、反应时间、醇酸比、TDI用量、饱和酸与不饱和酸配比、交联剂聚苯乙烯用量等对涂料性能的影响。研究表明:反应温度170℃,反应时间3 h,乙二醇、邻苯二甲酸酐与顺丁烯二酸酐物质的量比为1.4:3:7,—NCO与—OH物质的量比为1:1,每15 g树脂中加入交联剂苯乙烯5 g,固化体系0.3 g,填料10 g,可制得物理力学性能较好的聚氨酯型不饱和聚酯涂料,涂膜硬度为5 H,附着力1级,柔韧性0.5 mm,抗冲击性50 cm。     

Studies on the effect of anions of various lithium salts in PEMA gel polymer electrolytes

This research synthesized graft copolymers of chitosan‐g‐poly(N‐isopropyl acrylamide) (CS‐g‐PNIPAAm) by UV‐initiated free‐radical polymerization of NIPAAm monomer to CS selectively at the C‐6 position of pyranose ring. First, amino groups in CS were protected by reaction with phthalic anhydride (PA) to form PACS. The degree of phthaloylation was carefully controlled to ensure that most amino groups were protected, and only a very small amount of hydroxyl groups were reacted. In the second step, the vinyl functional group was introduced to the PACS by reaction with a vinyl compound containing an isocyanate group (3‐isopropenyl‐αα′‐dimethylbenzyl isocyanate), through the urethane linkage with hydroxyl groups at the C‐6 position. The phthaloyl groups were then removed by hydrazine to recover the amino groups in CS. Finally, PNIPAAm was grafted to the vinyl CS at the C‐6 position by UV‐initiated free‐radical polymerization. The synthesized CS‐g‐PNIPAAm copolymers were confirmed to have a structure of an AB‐crosslinked graft copolymer. Respectively, these copolymer hydrogels exhibited pH‐ and thermal‐responsive swelling properties in an aqueous solution due to their CS and PNIPAAm components. The test of cell viability with L929 fibroblast revealed that the CS‐g‐PNIPAAm copolymers having a grafting ratio lower than 1.7 had cellular compatibility as good as pure CS. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

2-[(1-羟基-2-萘基)羰基]苯甲酸的合成与表征

以苯酐和-α萘酚为原料,在B2O3催化下合成了2-[(1-羟基-2-萘基)羰基]苯甲酸,反应的优化条件为:n(B2O3)∶n(苯酐)∶n(-α萘酚)=1.5∶1.5∶1,反应温度为180￣190℃,反应时间为2.0h,收率达97.8%,并通过元素分析、1H NMR、IR、EIMS对产物结构进行了表征。     

UV固化萜烯聚酯丙烯酸酯的合成研究

以松节油-马来酸酐(TMA)、一缩乙二醇(DEG)、邻苯二甲酸酐(PA)、丙烯酸(AA)为主要原料合成了涂料用紫外光固化(UV)萜烯聚酯丙烯酸酯(TPEA)预聚物。通过分子质量、酯化率及涂膜性能测试以及GPC,TG分析以考察了原料物质的量比、合成工艺、反应温度等对TPEA树脂合成及涂膜性能的影响。结果表明,适宜的工艺条件为:TPEA酯化反应温度125℃,n(TMA)∶n(DEG)∶n(PA)∶n(AA)=1∶2.2∶0.5∶2,采用两步法,制备出的TPEA树脂综合性能较好。