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1.
以焦锑酸钠与巯基乙酸异辛酯为原料,用一步法合成了五(巯基乙酸异辛酯)锑,并用红外光谱对产品进行了分析.实验结果表明当焦锑酸钠与巯基乙酸异辛酯的量比为1.2∶1.0时, 以甲苯为溶剂, 加热回流3.5 h, 即可得到目标产物五(巯基乙酸异辛酯)锑, 其收率为92.8%;当五(巯基乙酸异辛酯)锑在PVC中的添加量为2.5%时, PVC的热稳定时间为40 min(200 ℃时);当其与硬脂酸钡复配时, 表现出协同作用.  相似文献   

2.
采用直接酯化的方法合成了三巯基乙酸正丁酯锑。并从实验的角度对其热稳定性能进行了研究,得出了三巯基乙酸正丁酯锑为PVC的高级热稳定剂的结论。  相似文献   

3.
聚氯乙烯/蒙脱土复合材料的动态热降解动力学   总被引:1,自引:0,他引:1  
采用热重分析仪研究了聚氯乙烯(PVC)/蒙脱土复合材料的热降解过程,比较了钠基蒙脱土(MMT)和烷基季铵盐改性的有机蒙脱土(OMMT)对PVC热稳定性和PVC热降解过程的影响.采用Friedman法研究了PVC和PVC/MMT(OMMT)复合材料的热降解动力学,并计算得到其表观活化能Ea.结果表明,在PVC热降解第一阶段,MMT和OMMT均能提高PVC的热分解温度和减少质量损失,从而提高PVC的热稳定性;PVC和PVC/MMT(OMMT)复合材料的Ea基本相近;MMT和OMMT对PVC的热降解速度有影响,但并没有改变PVc热降解机理.  相似文献   

4.
新型PVC热稳定剂——三(羟基乙硫醇)锑的合成   总被引:1,自引:1,他引:0  
研究了一种新型硫醇锑类热稳定剂———三 (羟基乙硫醇 )锑的合成及其应用 .实验时以三氧化二锑和巯基乙醇为原料 ,采用一步法直接化合生成三 (羟基乙硫醇 )锑 .此外 ,探讨了反应温度、反应物配比、反应时间等因素对产率的影响 .实验结果表明 :以二甲苯作为带水剂 ,反应物Sb2 O3与 6HSCH2 CH2 OH的量比为 1∶1 .2 ,加热回流 1 .0h ,得产品的收率为 93.8% ;三 (羟基乙硫醇 )锑为浅黄色液体 ,其折光率Dn2 0 为 1 .44 79;当三 (羟基乙硫醇 )锑的添加量为2 5份时 ,PVC树脂的热稳定时间为 46min(2 0 0℃时 ) .其热稳定性能优于钙 锌、铅盐复合热稳定剂 ,与二月桂酸二丁基锡的热稳定性能相当 .  相似文献   

5.
聚氯乙烯热稳定性测试方法的研究   总被引:1,自引:0,他引:1  
热稳定性是影响聚氯乙烯(PVC)加工和使用的重要性能之一,PVC热稳定测试方法的研究对PVC热稳定剂的研发起到至关重要的作用.从介绍PVC的降解机理入手,系统介绍和论述了白度法、变色法、刚果红法和电导法等聚氯乙烯稳定性能的测试方法,指出了不同测试方法的优缺点与适用范围.这些方法都以高温下聚氯乙烯降解释放HCl并生成共轭双键导致其颜色变化这一降解机理为依据来测试其稳定性.  相似文献   

6.
硬脂酸皂在工业生产中早已被使采用为聚氯乙烯(PVC)的稳定剂,但其对聚氯乙烯的稳定作用却仍需进行深入研究。本文研究了聚氯乙烯加进硬脂酸钡和硬脂酸镉后的热稳定性,以及环氧豆油、亚磷酸三苯酯对钡、镉皂稳定剂的稳定作用的影响。结果表明:1.钡、镉皂会加速PVC的受热失HCl作用,同时吸收PVC分解产生的HCl;而皂类和HCl反应所生成的氯化物对PVC失HCl有催化作用。2.钡,镉皂共同使用有协同怍用。3.环氧豆油和亚磷酸三苯酯对钡、镉皂的稳定作用有增效作用。提出了硬脂酸皂对PVC的热稳定作用,不在于抑制或减慢PVC的分解HCl,而可能是和PVC反应破坏因失HCl而生成的共轭双键;这样一方面起了抑制变色作用,另一方面使发生在双键上的降解和交联反应受到减弱,从而延缓了PVC的性能的受热破环,提高了聚氯乙烯的热稳定性。  相似文献   

7.
以五倍子制备的没食子酸和酒石酸锑钾为原料,研究了碱式没食子酸锑的合成条件。在筛选的合成条件下,产品收率(92%~95%)比文献收率(65%~70%)高。经过元素分析,红外光谱,热分析等方法测定,证实产品纯度高,稳定性好。  相似文献   

8.
利用Burley方法合成双二氯化锡,将之与巯基乙酸异辛酯,巯基丙酸异辛酯,十二硫醇及二硫醇反应,制备了一系列酯蜞锡化合物,新合成的酯基硫醇锡可作为PVC热稳定剂使用。  相似文献   

9.
利用Burley方法合成双(bata-烷氧基羰乙基)二氯化锡.将之与巯基乙酸异辛酯,巯基丙酸异辛酯,十二硫醇及二硫醇反应,制备了一系列酯基锡化合物.新合成的酯基硫醇锡可作为PVC热稳定剂使用  相似文献   

10.
以氧化锌和氰尿酸为原料,在弱酸性条件下制备了氰尿酸锌热稳定剂。通过红外光谱分析和X射线衍射对合成产物进行了表征分析。热重分析表明,氰尿酸锌作为PVC热稳定剂能钝化PVC链上的不稳定结构,吸收释放的氯化氢气体,抑制PVC的自催化作用,有效减缓PVC的热降解。通过静态刚果红测试、烘箱热老化测试和动态流变测试,测定了氰尿酸锌作为PVC热稳定剂的热稳定性能。结果表明:热稳定剂添加量为PVC的0.3%(质量分数)时,相比于硬脂酸锌,氰尿酸锌的热稳定性能更好,此时添加氰尿酸锌的PVC热稳定时间为18min,约为加硬脂酸锌热稳定时间的2倍;氰尿酸锌作为PVC热稳定剂的热稳定性能明显优于传统的硬脂酸锌热稳定剂,氰尿酸锌还能有效延长"锌烧"现象,与PVC有良好的相容性和润滑性。  相似文献   

11.
Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.  相似文献   

12.
何延凌 《科技信息》2008,(4):258-258
Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women's language from these perspectives: pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women's language, more attention should be paid to language use in social context. What's more, the linguistic phenomena in a speaking community can be understood more thoroughly.  相似文献   

13.
The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3~4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰~ -7.8‰, PDB) and matrix dolomites (-6.6‰~ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084~0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078~0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.  相似文献   

14.
理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。  相似文献   

15.
As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.  相似文献   

16.
AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…  相似文献   

17.
There are numerous geometric objects stored in the spatial databases. An importance function in a spatial database is that users can browse the geometric objects as a map efficiently. Thus the spatial database should display the geometric objects users concern about swiftly onto the display window. This process includes two operations:retrieve data from database and then draw them onto screen. Accordingly, to improve the efficiency, we should try to reduce time of both retrieving object and displaying them. The former can be achieved with the aid of spatial index such as R-tree, the latter require to simplify the objects. Simplification means that objects are shown with sufficient but not with unnecessary detail which depend on the scale of browse. So the major problem is how to retrieve data at different detail level efficiently. This paper introduces the implementation of a multi-scale index in the spatial database SISP (Spatial Information Shared Platform) which is generalized from R-tree. The difference between the generalization and the R-tree lies on two facets: One is that every node and geometric object in the generalization is assigned with a importance value which denote the importance of them, and every vertex in the objects are assigned with a importance value,too. The importance value can be use to decide which data should be retrieve from disk in a query. The other difference is that geometric objects in the generalization are divided into one or more sub-blocks, and vertexes are total ordered by their importance value. With the help of the generalized R-tree, one can easily retrieve data at different detail levels.Some experiments are performed on real-life data to evaluate the performance of solutions that separately use normal spatial index and multi-scale spatial index. The results show that the solution using multi-scale index in SISP is satisfying.  相似文献   

18.
In the 19th century the society was controlled by men, and women were just appendants of them, they had not any rights and freedom. But Jane was an exception, she showed some characteristics of early feminist. Jane showed her characteristics of feminism in three aspects: rebellion, equality, and independence. These characteristics were helpful to her success, and feminism is the only way out for women of that time.  相似文献   

19.
正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-  相似文献   

20.
We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-  相似文献   

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