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1.
采用熔融共混法制备了聚乙烯醇(PVA)/高密度聚乙烯(HDPE)共混物,引入马来酸酐接枝高密度聚乙烯(HDPE-g-MAH)对体系进行增容。利用SEM、小振幅震荡剪切、溶剂提取、拉伸测试考察组成和增容剂含量对共混物相形貌、动态流变性质、相连续性和力学性能的影响。结果表明,当HDPE质量分数达到20%~30%时,PVA/HDPE/HDPE-g-MAH共混物呈现接近共连续的结构;储能模量-频率图中观察到较为明显的第二平台;PVA相的连续度达到98%;共混物的断裂伸长率由5%显著提高到25%左右。另外,当HDPE-g-MAH的含量增大时,共混物的相界面变得模糊,力学性能也随之提高。  相似文献   

2.
通过甲酸和双氧水将液体端羧基丁腈橡胶(CTBN)中的双键氧化,制备液体环氧化端羧基丁腈橡胶(ECTBN),并将ECTBN用于环氧树脂增韧改性的研究。详细考察了环氧化反应的影响因素,并确定了最佳的环氧化反应条件。以哌啶为固化剂,分别制备了CTBN/环氧树脂和ECTBN/环氧树脂固化物。用扫描电镜和透射电镜观察了固化物的形态结构,发现CTBN以微米尺寸分散在基体中,而ECTBN则以纳米尺寸分散在基体中。分别对固化物的拉伸性能和冲击性能进行测试,结果表明,ECTBN对环氧树脂具有更好的改性效果。用ECTBN增韧环氧树脂,复合物的冲击强度与CTBN改性复合物相当,明显高于纯树脂;杨氏模量和拉伸强度明显高于CTBN改性复合物;环氧化程度越高,复合物的强度和模量越高。  相似文献   

3.
建立一种构型模拟与力学性能模拟相结合的连续模拟方法研究了三元共混物(两种均聚物与一种共聚物)中交替共聚结构与嵌段共聚结构对力学性能的影响。通过蒙特卡罗模拟获得其构型,然后将该构型作为弹簧格子模型的数据输入,模拟三元共混体系的微观结构与力学性能。模拟结果表明:交替共聚物在体系中更倾向于在两种均聚物的界面处自我缠绕,而嵌段共聚物的两端分别渗透进与之相容的均聚物体相中;三元共混物的力学性能与其内部的两相界面结构相关;应变在交替共聚物体系中均匀分布,导致更多的断裂发生在体相中,交替共聚物体系比嵌段共聚物体系力学性能更强且更具韧性。这种连续模拟方法为研究材料组成与力学性能之间的关系提供了一种新方案。  相似文献   

4.
用力学性能测试、DMA、SEM等方法研究了离聚物Surlyn对PBT/PP共混体系的力学性能及形态结构的影响。结果表明,在PBT/PP共混体系中引入少量Surlyn可以改善界面的粘接性,从而改善其力学性能。当共混体系中PBT/PP的组份比不变(90/10)且Surlyn的含量为6phr左右时,共混物的冲击强度出现极大值;而弯曲强度在Surlyn含量为1-2phr左右时有最大值。当共混体系中Surlyn的含量不变(6phr)时,其力学性能随PP含量的增加而下降。用玻璃纤维增强共混体系,可显著提高力学性能。  相似文献   

5.
研究了在聚丙烯(pp)与顺丁橡胶(BR)共混过程中加入橡胶硫化剂使共混体系中橡胶相动态硫化交联。研究结果表明,采用动态硫化法可提高共混物的冲击强度和拉伸强度。借助于SEM和DMA,证实了动态硫化使PP/BR共混体系具有相界面粘结良好的多相结构,改善了两相相容性。探讨了动态硫化增韧的机理。  相似文献   

6.
通过缩聚反应制备聚乙二醇-柠檬酸共聚物(PEGCA),通过密炼制备了PEGCA与聚乳酸(PLA)的共混物,研究了PEGCA对共混物的形貌结构、热性能和力学性能的影响。结果表明,PEGCA与PLA部分相容,PEGCA呈球状颗粒分散在PLA基体中。PEGCA对PLA有良好的增韧效果,当PEGCA质量分数为15%时,材料的断裂伸长率提高到327.9%,冲击强度提高到63.0 J/m。同时利用空穴化理论解释PEGCA增韧PLA的机理,用临界韧带厚度理论和J积分定量描述增韧的效果。  相似文献   

7.
通过原位聚合法,以密胺树脂(MF)为壁材,制备了微胶囊包覆聚磷酸铵(MCAPP),然后密炼将MCAPP与聚乳酸(PLA)熔融共混,得到微胶囊包覆聚磷酸铵阻燃聚乳酸,并研究了不同树脂包覆率的MCAPP对共混物形貌结构、加工性能、热性能、力学性能以及阻燃性能的影响。结果表明,在原位聚合过程中,当MF质量分数为17.2%时,MCAPP树脂包覆率可达13.2%,共混物中PLA结晶度提高,降解程度最低,同时阻燃效果最佳,极限氧指数可达39.4%,并且垂直燃烧等级达到UL94 V0级。  相似文献   

8.
通过TEM、SEM等方法研究了不同结构丙烯酸酯类抗冲改性剂(ACR)对聚氯乙烯(PVC/ACR共混体系形态结构的影响,对ACR增韧硬质PVC的机理作了探讨,当PVC中含有8phr以上完善核壳结构的ACR时,在共混体系能形成网络结构,这一结构在受冲击时产生多重银纹,并实现银纹的纯化,在PVC/ACR共混体系的增韧机理中占主导地位,同时,ACR诱发PVC产生剪切形变也是提高其增韧效果的因素。  相似文献   

9.
将热致性乙炔基封端液晶单体(MPBE)与含硅芳炔树脂(PSA)进行共聚,制得乙炔基封端液晶改性含硅芳炔树脂(PSA-MPBE)。采用FT-IR在线表征了PSA-MPBE树脂固化过程的结构变化,用裂解-气相色谱-质谱联用仪(Py-GC-MS)分析了其高温裂解产物,研究了其固化机理,用偏光显微镜(POM)、扫描电子显微镜(SEM)和透射电子显微镜(TEM)分析了共混树脂的相结构、断裂形貌和微观结构。结果表明:MPBE与PSA发生了共聚反应,使介晶域固定在交联网络中,形成结构均匀的以介晶相为小岛的海岛结构,PSA-MPBE树脂的断裂行为从典型的脆性断裂转变为微塑性断裂。  相似文献   

10.
通过动态力学谱试验(DMS)、应力-应变测量,研究了以丙烯腈、苯乙烯、醋酸乙烯酯等单体为共聚组分引入全(甲基)丙烯酸酯L′IPN(胶乳型互穿聚合物网络)中对共混体系阻尼性能、力学性能的影响,发现通过无规共聚引进不同链结构能有效调节材料室温域的阻尼水平;初步探讨了IPN(互穿聚合物网络)中某些组分侧链(基)结构对阻尼性能的影响规律及可能原因;本文所研究的IPN体系在力学(物理)状态上处于皮革态,而交联密度、组分含量等对IPN的力学性能具有较为复杂的影响。  相似文献   

11.
FOR anesthesiologis s ,treatingpostoperativepainhas alwaysbeen a problem.Althoughopioidshave been provedtobe effective,theirsideeffectscouldnotbeignored.With thedevelopmentofscienceand pharmacology,many drugs with aspectsof satisfactoryanalgesicefficacyand couldbe welltoleratedby patientshave been developed.And lornoxicamisone of them, which isa non-steroidalanti-inflammatorydrug (NSAID ), with analgesic, anti-infl-ammatory,andantipyreticproperties.Itseliminationhalf-time(3 to 5 hours) isle…  相似文献   

12.
Dr.Zhang Ren,the chief physician,is the chairman of Shanghai Acupuncture and Moxibustion Association.Having been engaged in medicine for about 40 years,he is experienced in treating various intractable diseases.In his long years of clinical practice,he advocates taking the TCM differentiation as the basis to seek for the acupuncture method for treatment of modern intractable diseases.The author of this essay had the fortune to follow Dr.Zhang in study.The following is a summary of Dr.Zhang's experience in the acupuncture treatment for different intractable diseases with the same therapeutic principle.  相似文献   

13.
In treating chronic nephropathy,Luo Lingjie,a chief physician,pays attention to regulating the balance between yin and yang,treating infection if present,and removing pathogenic factors.He prescribes gentle drugs and uses carefully strongly warming-tonifying ones,emphasizes the importance of persuading the patient to persist in treatment with medication and nurse one's health for recuperation,and is good at combined use of TCM and western medicine therapy and brings the merits of various therapies into full play,with obvious theraoeutic effects.  相似文献   

14.
Objective: To observe the therapeutic effects in acupunture treatment of primary dysmenorrhea combined with spinal Tui Na, and study its mechanism. Methods: Thirty cases of the treatment group were treated by acupuncture combined with spinal Tui Na, and thirty cases in the control group were treated by routine acupuncture. Results: The total effective rate was 93.3% in the treatment group, and 73.3% in the control group, with a significant difference between the two groups (P<0.05). Conclusions: Acupuncture combined with spinal Tui Na has good prospects for treatment of primary dysmenorrhea.  相似文献   

15.
16.
目的 探讨猪肺磷脂注射液联合经鼻持续气道正压通气(NCPAP)对呼吸衰竭早产儿的临床疗效及肌酸激酶同工酶活性(CK-MB)的影响.方法 选取呼吸衰竭早产儿80例,分为观察组和对照组各40例.对照组采用NCPAP给氧治疗,观察组给予NCPAP给氧联合猪肺磷脂气管内给药.观察两组患儿治疗前及治疗12h、24 h后PaO2、PaCO2、血氧饱和度(SaO2)、pH的变化情况,检测治疗前及治疗5d后血清CK-MB水平;评估两组患儿的临床治疗效果.结果 两组患儿PaO2、PaCO2、SaO2、pH比较,差异均有统计学意义(P<0.05),其中观察组治疗后的PaO2、SaO2、pH均高于对照组,PaCO2则低于对照组.两组的PaO2、SaO2、pH均随观察时间延长而升高(P<0.05),PaCO2均随观察时间的延长而降低(P<0.05).观察组治疗有效率为87.5%,显著高于对照组的70.0% (P <0.05).治疗5d后两组患儿血清CK-MB水平均较前降低(P<0.05),且观察组明显低于对照组(P<0.05).结论 猪肺磷脂注射液气管内给药联合NCPAP可以显著降低呼吸衰竭早产儿CK-MB的含量,提高治疗有效率,起到很好的呼吸循环支持作用.  相似文献   

17.
CASE HISTORY A female patient, 46 years old, head of the foreign affairs department of a certain university in Beijing, paid her first visit on October 9, 2006, with the chief complaint of vomiting for one month. She got vomiting after meals in early September. Before that, she had discomfortable sensation in the stomach due to angry with others, but she didn't pay much attention. Later, it developed into vomiting after eating. After the vomiting, the discomfort would be relieved, but with slight hypodynamia. She was once diagnosed as having 'neurogenic vomiting'. Having taken some western and Chinese drugs, the above symptoms were a little bit improved, but she would have nausea upon eating and with regurgitation. Because of the fear for vomiting, she did not dare to have food intake, with body weight reduction of 6 kilos in one month.  相似文献   

18.
Radiotherapy and chemotherapy are the important modern medical therapies for malignant tumors,yet they can also bring about serious local and systemic toxic side reactions so to decrease the patient;'s life quality,manifested by a series of consumptive symptoms.Having engaged in the combined work of Chinese and western medicine for nearly 50 years,the research fellow Qiu Baoguo in Henan Provincial Academy of TCM has developed his unique views on the TCM study of consumptive syndromes.The author of this essay had once the fortune tO follow Dr.Qiu in clinic,and specially would like to introduce in the following Dr.Qiu's experience in treating consumptive syndromes after radio-chemotherapies for patients with malignant tumor.  相似文献   

19.
OBJECTIVE: To observe therapeutic effects of the comprehensive therapy of acupuncture-moxibustion and Chinese Tuina for treatment of insomnia due to deficiency of both the heart and spleen. METHODS: 92 cases were divided randomly into the treatment group (treated by acupuncture-moxibustion and Chinese Tuina) and the control group (treated by acupuncture-moxibustion). RESULTS: The therapeutic effect of the treatment group was obviously superior to that of the control group (the CHI2 test showed P < 0.01). CONCLUSIONS: The comprehensive therapy of acupuncture-moxibustion and Chinese Tuina can give marked therapeutic effects for treatment of insomnia due to deficiency of both the heart and spleen.  相似文献   

20.
Evidence obtained from randomized controlled trials (RCTs) has been generally accepted as the gold standard in the evaluation of clinical effectiveness. Readers need to understand the trial design, implementation, results, analysis and interpretation, so as to fully Jnderstand the results of RCTs. Thus, the investigators of RCTs have to report these items in a complete, accurate and clear manner. Since 1998, we have conducted several evaluations on the reporting quality of RCTs published in Chinese journals on traditional Chinese medicine (TCM) and results have shown that there is an urgent need for higher quality RCTs on TCM.  相似文献   

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