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1.
以1,4-环己烷二甲醇(CHDM)、对苯二甲酸(PTA)、均苯四甲酸酐(PMDA)和异氰尿酸三缩水甘油酯(TGIC)为原料,通过直接酯化、减压缩聚和熔融扩链的方法制备了一系列分子量可控的芳香族聚酯——聚对苯二甲酸-1,4-环己烷二甲醇酯(PCT)。采用傅里叶红外光谱(FT-IR)、凝胶渗透色谱(GPC)、差示扫描量热(DSC)、热重分析(TG)、广角X-射线衍射(WXRD)、电子万能试验机分别研究了其分子结构、热性能和力学性能。结果表明:当n(CHDM):n(PTA)=1.2时,用复配催化剂钛酸四丁酯(TBT)、二氧化锗(GeO2)、三氧化二锑(Sb2O3)(用量均为0.1 mg/g)以及醋酸钴(Co(Ac)2)(用量为0.05 mg/g),290℃下缩聚3 h得到数均分子量较大的PCT,特性黏数([η])为0.560 dL/g。PMDA-TGIC联用扩链可以获得特性黏数为0.680 dL/g的扩链PCT,用其制备的薄膜拉伸强度可达27.6 MPa。  相似文献   

2.
以1,4 丁二酸、1,4 丁二醇和1,2 己二醇为原料,采用直接熔融缩聚的方法,合成得到聚丁二酸丁二醇酯(PBS)和一系列聚(丁二酸丁二醇酯 co 丁二酸1,2 己二醇酯)(PBSH)共聚物。采用乌氏黏度计、1H NMR、DSC和流变仪等手段对其分子量、化学结构、热学性能、流变行为和力学性能进行研究。结果显示:随着1,2 己二醇摩尔分数的增加,相应PBS共聚酯的熔点(Tm)、结晶温度(Tc)、结晶度(Xc)、弯曲强度、拉伸强度逐渐降低,断裂伸长率明显增加;另外,1,2 己二醇的加入对PBS的零切黏度(η0)、储能模量(G′)和损耗模量(G″)也有一定的影响。  相似文献   

3.
研究在间歇高压反应器中聚对苯二甲酸乙二醇酯(PET)、聚对苯二甲酸丁二醇酯(PBT)及聚碳酸酯(PC)在超临界甲醇中的降解反应;通过建立聚酯在超临界甲醇中的降解反应模型,探讨了聚酯在甲醇中降解的机理。结果表明:PET、PBT和PC在甲醇溶液中的降解具有共性,均可分为超临界区、非临界区和中间过渡区三个区域。在超临界区聚酯完全溶于甲醇并降解为原料单体,且对苯二甲酸二甲酯(DMT)和碳酸二甲酯(DMC)的收率均大于90%;聚酯的降解是在聚合物分子链的无规断裂和聚酯进行酯交换反应的双重作用下发生的。  相似文献   

4.
对亚磷酸烷酯与丁烯二酸二烷酯的加成反应,以及膦酸丁二酸四烷酯与丙烯酸烷酯的加成反应的机理进行了讨论。提出了由亚磷酸二乙酯、反丁烯二酸二乙酯、丙烯酸乙酯等为反应原料,在碱性催化剂作用下经三步反应得到2-膦酸丁烷-1,2,4-三羧酸(PBTCA)的合成途径,产品得率为76%。采用谱学方法等初步证实了合成产物及其中间体的分子结构。并且对PBTCA的物化性质进行了探讨。  相似文献   

5.
以酯交换反应合成了聚丁二酸酯系列,与高氯酸锂制成固体电解质。通过对聚酯及其电解质的热失重分析,将其热分解进行了动力学处理,结果表明这一系列聚酯分解温度相近,与链节单元长度无关;聚酯电解质的热稳定性比聚酯差,且随无机盐含量提高而降低。利用色-质谱联用技术,剖析了聚酯及其固体电解质的分解产物,提出了它们各自的分解机理。  相似文献   

6.
以芳香二元酸为聚丁二酸丁二醇酯的共聚组分,合成了一系列聚丁二酸丁二醇酯(PTS)共聚物,用土埋法和二氧化碳释放法测定其生物降解性,发现一定比例的共聚酯具有良好的生物降解性。  相似文献   

7.
目的 合成阿昔洛韦琥珀酰亚胺活性酯.方法 以阿昔洛韦为起始原料,在二甲基甲酰铵(DMF)为溶媒及三乙胺的碱性条件下,与丁二酸酐反应生成阿昔洛韦衍生物9-(2-丁二酸单酰乙氧基甲基)鸟嘌呤(SACV),再与N-羟基琥珀酸亚胺在N,N-二环己基碳化亚胺的存在条件下合成阿昔洛韦琥珀酰亚胺活性酯.结果 与结论合成产物产率为79.1%,mp为125~126 ℃,其结构经IR和NMR确证,所得化合物为一新化合物.  相似文献   

8.
环状碳酸乙烯酯(EC)分别与乙二胺、己二胺开环反应合成1,2-乙二氨基甲酸羟乙酯(EDHU)与1,6-己二氨基甲酸羟乙酯(HDHU),用FT-IR、1H-NMR、13C-NMR等手段对其结构进行表征并作为扩链剂与二异氰酸酯(MDI)、聚酯多元醇反应制备聚氨酯热熔胶,对热熔胶的黏结性能、结晶性能、微相分离程度、表面张力及流变性能进行研究,结果表明:EDHU与HDHU作为扩链剂合成的聚氨酯热熔胶的微相分离程度分别为91.2%和83.9%,与传统的1,4-丁二醇(BDO)扩链剂合成的热熔胶相比,EDHU合成的热熔胶黏结强度提高了20%。  相似文献   

9.
本文用相转移催化方法合成了四种新颖的芳香族聚酯。对所得聚合物进行了红外光谱、热重分析、偏光显微镜、示差扫描量热仪和解偏振光强等测试,以研究它们的结构和性能。它们的热分解温度都在330℃以上。其中的聚对,对′-1,4,7-三氧杂庚撐基二苯甲酸对苯二酚酯和聚对苯二甲酸对,对′-1,8-二氧杂辛撐基二苯酚酯,呈现向列型相转变,它们的清晰点分别为237℃和327℃。其它两种含双酚A或酚酞基团的聚酯则不存在液晶行为。对实验结果进行了讨论。  相似文献   

10.
本文以对羟基苯甲酸酯和对苯醌为原料,经七步反应合成下列结构的系列化合物。(其中R=n-C_3H_7,n-C_5H_(11),n-C_6H_(13),n-C_9H_(19)和n-C_(10)H_(21)) 对反-4-烷氧基环己烷羧酸的合成制定了一条新的路线;2,3-二氰基-1,4-苯二酚的合成产率比文献值提高9%左右;并对上述化合物进行了元素分析和红外光谱、液晶性能的测定。该类化合物的熔点和澄清点较高,相变温度较宽,是一种较为理想的混合液晶材料。  相似文献   

11.
Objective: To evaluatel the value of D-dimers in patients with acute aortic dissection (AAD). Methods: This study consisted of 16 patients with AAD and 27 non-AAD patients. Serum D-dimets were measured by Sta-Liatest D-DI immunoturbidimetric assay. Results: D-dimer level was higher (P < 0.001) in patients with AAD(7.91 ± 5.52 μg/ml) than that in non- AAD group(1.57±1.24 μg/ml). D-dimer was positive (>0.4 μg/ml) in all patients with AAD and in 10 control group patients (37%). Among patients with acute AAD, D-dimers tended to be higher in Stanford A than in Stanford B (8.67 ± 4.31 μg/ml vs. 3.24±1.27 μg/ml, P <0.01). D-dimer values tended to be higher in more extended disease(3.84 ± 1.65 μg/ml, 8.57 ± 3.58 μg/ml and 11.87 ± 5.69 μg/ml in thoracic aorta, thoracic and abdominal aorta, thoracic and abdominal aorta and iliacal arteries, respectively, P < 0.05 for both 8.57 ± 3.58 and 11.87 ± 5.69 vs. 3.84 ± 1.65 ). Including the control group into the analysis, we found a sensitivity of 100%, a negative predictive value of 100%, and a specificity of 66% and a positive predictive value of 64% for D-dimer in diagnosis of AAD in our patients with suspected AAD. Conclusion: D-dimer was elevated in patients with AAD. A negative D-dimer test result could be useful in excluding AAD.  相似文献   

12.
Objective: To set up a simple and reliable rat model of combined liver-kidney transplantation. Methods: SD rats served as both donors and recipients. 4℃ sodium lactate Ringer's was infused from portal veins to donated livers,and from abdominal aorta to donated kidneys, respectively. Anastomosis of the portal vein and the inferior vena cava (IVC) inferior to the right kidney between the graft and the recipient was performed by a double cuff method, then the superior hepatic vena cava with suture. A patch of donated renal artery was anastomosed to the recipient abdominal aorta. The urethra and bile duct were reconstructed with a simple inside bracket. Results: Among 65 cases of combined liver-kidney transplantation, the success rate in the late 40 cases was 77.5%. The function of the grafted liver and kidney remained normal. Conclusion: This rat model of combined liver-kidney transplantation can be established in common laboratory conditions with high success rate and meet the needs of renal transplantation experiment.  相似文献   

13.
Objective To observe blood pressure change with age in salt-sensitive teenagers whose salt sensitivity were determined by repeated testing.Methods Salt sensitivity was determined through intravenous infusion of normal saline combined with volume-depletion by oral diuretic furosemide in 55 teenagers. After five years, salt sensitivity was re-examined and subject blood pressure was followed up. Blood pressure changes in salt-sensitive teenagers were compared to that of non-salt sensitive teenagers over five years.Results After 5 years, the repetition rate of salt sensitivity determined by intravenous saline loading is 92.7%. In teenagers with salt sensitivity on the baseline, both the systolic blood pressure increments and increment rates were much higher than non-salt sensitive teenagers (12.7±12.1 mmHg vs. 2.8±5.2 mmHg, P< 0.01; 12.2%± 12.0% vs. 2.5% ±4.4%, P< 0.001,respectively). There was a similar trend for diastolic blood pressure (8.4 ± 6.4 mmHg vs. 3.7 ± 6.4 mmHg, P = 0.052; 13.2% ±10.6 % vs. 6.8%± 10.1%, P = 0.053, respectively).Conclusions Salt sensitivity determined by intravenous saline loading showed good reproducibility. Blood pressure increments with age were much higher in salt-sensitive teenagers than non-salt sensitive teenagers, especially in terms of systolic blood pressure.  相似文献   

14.
目的:评价使用安心颗粒对急诊经皮冠状动脉介入术(PPCI)术后生活质量的影响.方法:将160例接受PPCI的急性ST段抬高型心肌梗死患者随机分为安心颗粒组(术前顿服安心颗粒8.8g,术后安心颗粒4.4 g/次,每日2次)和对照组(仅接受基础药物治疗).所有患者均服用阿司匹林、氯吡格雷和阿托伐他汀.分别在入院时、出院前1d、出院后180 d时,应用心肌梗死多维度量表(MIDAS)、中文版SF-36评价量表对患者生活质量评分.并观察术后30 d以内的出血并发症、血小板减少症发生情况.结果:入院时和出院前1d,两组患者的心肌梗死MIDAS、SF-36量表评分比较无差异(P>0.05);出院后180 d时,与对照组比较,安心颗粒组MIDAS、SF-36评分明显减低(P<0.05);组内与入院时比较,两组出院前1d、出院后180 d时,MIDAS、SF-36评分均降低(P<0.05).两组患者在随访期间均无大量出血、少量出血、重度和极重度血小板减少症发生,安心颗粒组有4例、对照组有7例发生不明显出血(P>0.05).两组发生轻度血小板减少症的患者数比较无差异(P>0.05).结论:PPCI使用安心颗粒,能改善急性ST段抬高型心肌梗死患者的生活质量,且不增加出血风险.  相似文献   

15.
Objective:To investigate the influences of urapidil and nicardipine on rabbit sinus function,atrio-ventricular node function and hemodynamics.Methods:Thirty-two Angora's rabbits were selected and randomly divided into four groups.U1 group:urapidil 0.25 mg/kg;U2 group:urapidil 0.5 mg/kg;N1 group:nicardipine 10 μg/kg;N2 group:nicardipine 20 μg/kg.All these medicine were administrated within 30 seconds.Measurements were taken before and after the administration of urapidil or nicardipine for the following data:mean blood pressure(MAP),heart rate(HR),sino-atrial conduction time(SACT),maximal sinoatrial recovery time(SNRTmax)corrected sinus node recovery time(CSNRT),index of sinus node recovery time(SNRTI),Wenckebach A-V conduction frequency (WB),and P-R interval.Results:Significant MAP and HR changes were identified in all of the four groups before and after administration of both urapidil and nicardipine.No significant changes could be found in the rest of the parameters.Intergroup analysis showed that SACT and CSNRT of N1 and N2 groups were shorter than those of the U2 group(P<0.01);the MAP decreased(P<0.01)and the HR increased drastically(P<0.01).Conclusions:Neither urapidil(0.25 mg/kg,0.5 mg/kg)nor nicardipine(10μg/kg,20μg/kg)has any significant influence on rabbit sinus function or rabbit atrio-ventricular node function.Nicardipine could be a better choice than urapidil for parafunctional sinus node patients.  相似文献   

16.
Objective:To investigate the gene expression of osteoprotegerin(OPG) and osteoclast differentiation factor(ODF) in the bone tissue of patients with hip fracture due to osteoporosis. Methods:OPGmRNA and ODFmRNA in the bone tissue in 50 cases of osteoporosis sufferers(over 50 years old) with hip fracture(Observer Group) and 30 cases of hip facture sufferers with no osteoporosis(Control group) were analyzed with the Semi-Quantitative RT-PCR method. Results:The mRNA expressed of ODF, OPG were both high in the patients with hip fracture. In the control group, the expression of OPG mRNA was observed, while the expression of ODF mRNA was very slight. Conclusion:Aged patients contained all signals including OPG, ODF that are essential for inducing osteoclastogenesis and promoting bone resorption.  相似文献   

17.
Objective:To investigate the clinical features, pathological characteristics and immunophenotype of solid-pseudopapillary tumor of the pancreas(SPTP). Methods:Nine surgically treated cases of SPTP were retrospectively reviewed. Hematoxylin and Eosin(HE) staining and immunohistochemical staining were used to analyze all cases, and the general clinical data was collected. Results:Six patients were asymptomatic except for a palpable mass. Two patients complained of vague-epigastric pain. One patient appeared jaundice. The tumor was encapsulated and solid tissues alternately with cystic tissues. Histologically, the histological structure of solid portion was pseudopapillary with a fibrovascular core. Tumor cells were uniform and medium-sized which were arranged in sheets ets or nests or pseudopapillary patterns. Immunohistochemical studies demonstrated that SPTP proved positive in vimentin(9/9 cases), AAT(9/9 cases), NSE(9/9 cases), ACT(7/9 cases), CK20(2/9 cases), CgA(1/9 cases), S-100(3/gcases), PR(4/gcases), Syn(3/9 cases) and CD56(5/9cases), negative in CEA and ER. Conclusion:SPTP is a tumor predominantly occurring in young women frequently without special symptoms. This tumor has various characteristical histological patterns with different immunophenotype.  相似文献   

18.
Objective:To probe into the influence of changes of ovarian hormones on the pathogenesis of the specific sub-type premenstrual syndrome(PMS)and reveal partial microcosmic mechanisms of adverse flow of liver-qi.Methods:Estradiol(E2)and progesterone(P)levels in serum were determined at different phases of menstrual cycle by radioimmunoassay.Results:In the group of PMS with adverse flow of liver-qi.the secretive peak value Of E2 and P at the follicular phase significantly decreased,and the secretive peak value at the luteal phase did not come into being.Conclusions:Low E2 and P secretive peak at the follicular phase and absence of secretive peak at the luteal phase is one of the microcosmic mechanisms of PMS with adverse flow of liver-qi.One of the pathophysiologic mechanisms of specific sub-type PMS is probably the continuous low level of E2and P.  相似文献   

19.
Real-time three-dimensional echocardiography (RT3DE)is a new ultrasound technique that enables dynamic threedimensional visualization and quantification of the heart in real time. Investigation of feasibility and methodology of RT3DE in determining left ventricular (LV) and right ventricular (RV) volumes, RT3DE was performed in 35 normal adults using Philips SONOS 7500 system with a 2-4 MHz matrix array transducer. The 60°×60° "pyramid" volume database was obtained and analyzed on a TomTec echo workstation. Both LV and RV volumes were calculated with four 3DE methods (i.e. apical 2, 4, 8, and 16-plane) through manually tracing ventricular endocardial borders in end diastole and end systole. Stroke volumes were then calculated. LV volume was also measured by 2DE Simpson's rule using GE VIVID 7 ultrasound machine.  相似文献   

20.
Increasing maternal age is the only etiological factor unequivocally linked to Down's syndrome in humans. The occurrence rate of newborns with Down's syndrome is about 1/220 in women over 35 years old. However, the occurrence rate in embryos fertilized in vitro, of the elder woman is unclear. Using FISH we screened the number of chromosome 21 in preimplanted embryos of 5 elderly women (average age, 38.4 years) to study the feasibility and necessity of screening trisomy 21 in embryos in patients over 35 years old at the in vitro fertilization (IVF) center.  相似文献   

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