讲解导体及半导体转变的共轭结构.doc

讲解导体及半导体转变的共轭结构聚苯胺的化学合成是在酸性介质中用氧化剂使苯胺单体氧化聚合。化学法能够制备大批量的聚苯胺样品，也是最常用的一种制备聚苯胺的方法。用hci作介质，用(nh4)2s208作氧化剂，一次性可用22500g苯胺合成聚苯胺。化学法合成聚苯胺主要受反应介质酸的种类、浓度。氧化剂的种类及浓度，单体浓度和反应温度、反应时间等因素的影响。Chemical synthesis of polyaniline is in acidic medium with antioxidant oxidation polymerization of aniline monomer. Chemical method to the preparation of large quantities of polyaniline samples, which is the most commonly used a method of preparation of polyaniline. Using hci as medium, using (nh4) 2 s208 as oxidant, one-time use 22500 g aniline synthesis of polyaniline. Chemical synthesis of polyaniline is mainly affected by reaction medium type, concentration of acid. The kinds and concentrations of oxidizing agent, monomer concentration and reaction temperature, reaction time and so on factors. 1酸的种类及其浓度对合成聚苯胺性能的影响。1 acid type and concentration of effect the performance of the synthesis of polyaniline. 苯胺在hci,hbr,h2so4,hcio4,hno3,ch3cooh,hbf4及对甲苯磺酸等介质中聚合都能得到聚苯胺，而在h2so4,hci,hcio4体系中可得到高电导率的聚苯胺，在hno3,ch3cooh体系中所得到的聚苯胺为绝缘体。非挥发性的质子酸h2so4,hcio4最终会残留在聚苯胺的表面，影响产品质量，最常用的介质酸是hci。质子酸在苯胺聚合过程中的主要作用是提供质子，并保证聚合体系有足够酸度的作用，使反应按1，4-偶联方式发生。只有在适当的酸度条件下，苯胺的聚合才按1，4-偶联方式发生。酸度过低，聚合按头一尾和头一头两种方式相连，得到大量偶氮副产物。当酸度过高时，又会发生芳环上的取代反应使电导率下降。当单体浓度为0.5mol.l-1时，最佳酸浓度范围为1.02.0mpl.l-i。Hcio4 aniline in hci, six HBR, - h2so4, hno3, ch3cooh, hbf4 and p-toluene sulfonic acid medium, such as polymerization can be polyaniline, and in - h2so4, hci, hcio4 system in the high conductivity of polyaniline can be obtained, in hno3, ch3cooh system of polyaniline as insulators. Non-volatile proton acid - h2so4 hcio4, eventually will remain on the surface of polyaniline, affect the product quality, the most commonly used medium acid is hci. Proton acid in aniline polymerization process, the main function is to provide the proton, and ensure the polymerization system have enough acidity, the reaction occurred in 1, 4 - coupling way. Only under the condition of proper acidity, the polymerization of aniline was happened in 1, 4 - coupling way. Too low acidity, aggregate according to the first end and a head of one of two ways is linked together, get a lot of azo by-products. Will happen when the acidity is too high, and the substitution reaction of aromatic ring made conductivity decreased. When the concentration of monomer is 0.5 mol. L - 1, the best acid concentration in the range of 1.0 1.0 MPL. L - I. 2氧化剂种类及其浓度对合成聚苯胺性能的影响2 oxidant species and concentration on the influence of the synthesis of polyaniline 苯胺聚合常用的氧化剂有：(nh4)2s2o8,k2cr2o7,kio3,h22,fecl3等。也有用(nh4)2s2o8和碳酸酯类过氧化物组成复合氧化剂制备聚苯胺。以fe2+为催化剂和h2o2为氧化剂可合成高溶解性的聚苯胺。(nh4)2s2o8不含金属离子，后处理简便，氧化能力强，是最常用的氧化剂。在一定范围内，随着氧化剂用量的增加，聚合物的产率和电导率也增加。当氧化剂用量过多时，体系活性中心相对较多，不利于生成高分子量的聚苯胺，且聚苯胺的过氧化程度增加，聚合物的电导率下降。当用(nh4)2s2o8合成聚苯胺时，过硫酸铵与苯胺的摩尔比为1.0时，聚合物的电导率最高，过硫酸铵与苯胺的摩尔比为1.5时，产率最大。Aniline polymerization of oxidant with (nh4) 2 s2o8 and k2cr2o7, kio3, h22, fecl3, etc. Also useful (nh4) 2 s2o8 and carbonic acid ester peroxide compound preparation of polyaniline. With fe2 + as catalyst and h2o2 as oxidant can synthesize the high solubility of pani. (nh4) 2 s2o8 do not contain metal ions, post processing is simple, strong oxidation ability, is the most commonly used oxidant. Within a certain range, with the increase of dosage of oxidant, the yield of the polymer and the conductivity increases. When excessive dosage of oxidant, the system of active center is relatively more, unfavorable to generate high molecular weight of polyaniline, and polyaniline peroxide level increases, the conductivity of polymers. When using (nh4) 2 s2o8 synthetic polyaniline, ammonium persulfate and the molar ratio of aniline to 1.0, the electrical conductivity of polymer is highest, the molar ratio of ammonium persulfate and aniline was 1.5, the yield is the largest. 3反应温度及单体浓度对合成聚苯胺性能的影响3, reaction temperature and monomer concentration on the influence of the synthesis of polyaniline 反应温度对聚苯胺的电导率影响不大，在低温下(0左右)聚合有利于提高聚苯胺的分子量并获得分子量分布较窄的聚合物。在过硫酸铵体系中，在一定温度范围内。随着反应体系温度升高，聚合物的产率增加，羟丙基甲基纤维素当温度为30时，产率最大。苯胺聚合是放热反应，且聚合过程有一个自加速过程。如果单体浓度过高会发生暴聚，一般单体浓度取0.250.5moll-l为宜。Reaction temperature on the conductivity of polyaniline, at low temperature (0 or so) polymerization to improve the polyaniline polymer molecular weight and narrow molecular weight distribution. In the ammonium persulfate system, to a certain temperature range. With increasing temperature of reaction system, the yield of the polymer increases, when the temperature is 30 , the yield is the largest. Aniline polymerization is exothermic reaction and polymerization process has a process from acceleration. Violence would happen if high monomer concentration, monomer concentration in 0.25 0.5 moll commonly - l is advisable. (二)电化学聚合法(2) the electrochemical polymerization 聚苯胺的电化学聚合法主要有：恒电位法、恒电流法、动电位扫描法以及脉冲极化法。一般都是酿酒设备苯胺在酸性溶液中，在阳极上进行聚合。电极材料、电极电位、电解质溶液的ph值及其种类对苯胺的聚合都有一定的影响。操作过程如下：氨与氢氟酸反应制得电解质溶液，以铂丝为对电极，铂微盘电极为工作电极，cucuf，为参比电极，在含电解质和苯胺的电解池中。复合土工膜以动电位扫描法(e=0.6-2.0v)进行电化学聚合，反应一段时间后，聚苯胺便牢固地吸附在电极上，形成坚硬的聚苯胺薄膜。Polyaniline of electrochemical polymerization are: constant voltage, constant current, potentiodynamic scanning polarization method and pulse method. Are generally not of aniline in acidic solution, aggregated on the anode. Electrode material, electrode potential, ph value and kinds of electrolyte solution has certain effect on the polymerization of aniline. Operation process is as follows: ammonia reaction with hydrofluoric acid, electrolyte solution was to platinum wire as electrode, micro disk platinum, nano-sno2 electrode was cu/cuf, as the reference electrode, and aniline electrolysis pool in the electrolyte. With potentiodynamic scanning method (e = 0.6 to 2.0 v) for electrochemical polymerization, reaction after a period of time, polyaniline has firmly adsorbed on the electrode, forming hard polyaniline thin film. 二、聚苯胺的应用Second, the applications of polyaniline (一)聚苯胺在金属防腐领域的应用(a) application in the field of pani in metal corrosion 1985年，deberry发现，在酸性介质中用电化学法合成的聚苯胺膜能使不锈钢表面活性钝化而防腐，这一特点引起了人们的关注，从此人们在腐蚀防护领域开始了导电高分子膜的应用研究，苏慈生教授已对聚苯胺的化学结构，防腐蚀机理及应用前景作了很好的介绍。当前最有效的金属防腐蚀颜料仍然是六价铬化物及含铅的化合物，六价铬化合物是致癌物质，铅也是严重污染环境的重金属，聚苯胺涂料被看好是新一代环境可接受的高效防腐涂料。因为水性油墨聚苯胺无毒，且在金属的防护中不但具有机械隔离作用，而且具有一定的催化钝化作用。当金属表面的聚苯胺有缺损时，它对该部位起一种催化钝化作用，使缺损聚苯胺涂层的金属裸露部分在酸性条件下，发生阳极氧化反应，快速恢复表面钝化层。作为防腐涂料，无论从试验室结果还是实际检测结果来看，聚苯胺都是较为理想的，尤其是其特有的抗腐蚀、抗划伤能力更是单纯环氧涂层不可比拟的。其主要应用领域包括：船舶、港口码头设备、远洋集装箱、军舰、两栖装甲、化工设备、高压铁塔、送变电设备、铁路桥梁等耐久性防腐材料。Deberry found in 1985, in acid medium by electrochemical synthesis of polyaniline film can make the stainless steel surface passivation active and anticorrosion, this characteristic caused the attention of people, from then on, people began in the field of corrosion protection of the conductive polymer film applied research, professor Su Cisheng has chemical structure of polyaniline anticorrosion mechanism and introduce a good application prospect. Current metal anticorrosion paint is still the most effective hexavalent chromium compound and lead compounds, compounds hexavalent chromium is a carcinogen, lead and serious environmental pollution of heavy metals, environment that is a new generation of polyaniline coatings were acceptable efficient anticorrosion coatings. Because of polyaniline non-toxic and in metal protection not only have mechanical isolation effect, and has a certain catalytic deactivation. When polyaniline on the surface of the metal has a defect, it plays a role of a catalyst passivation for the region, the defects of polyaniline coating in acidic conditions, bare metal part of the anodic oxidation reaction, fast recovery surface passivation layer. As anticorrosive coatings, either from the perspective of laboratory results and actual test results of polyaniline is ideal, especially its unique corrosion resistance, scratch resistance ability is incomparable pure epoxy coating. Its main application fields include: shipping, port terminals, ocean containers, ships and amphibious armored, chemical equipment, high-voltage tower of electricity transmission &transformation facilities equipment, railway bridge durability, anticorrosive material. (二)聚苯胺在电磁屏蔽材料方面的应用(2) of polyaniline in the field of electromagnetic shielding material application 随着电器制品和电子器件的商业应用、军事应用和科学应用的迅速增长，电磁干扰也称作电磁环境污染问题日渐严重，电磁干扰屏蔽日益受到关注。导电聚苯胺具有重量轻、韧性好、易加工和电导率易于调节的优势，所以是一种优良的电磁屏蔽材料。文献报道，在频率范围10mhz1ghz之间，用高导电率的聚苯胺作屏蔽材料，可得到20db以上的屏蔽效力。高导电聚苯胺薄膜的厚度超过20um时，其屏蔽效力大于40db，可以满足民用标准。但用导电聚苯胺作电磁屏蔽材料时，目前存在的关键问题是聚苯胺的电导率还不够高。因此，提高聚苯胺的电导率是今后的主要研究目标。As the electrical appliances and electronic devices, military and scientific application of business applications, the rapid growth of electromagnetic interference is also called electromagnetic pollution of the environment problem increasingly serious, electromagnetic interference shielding is becoming more and more attention. Conductive polyaniline with light weight, good toughness, easy processing and the advantage of conductivity is easy to adjust, so it is a good electromagnetic shielding material. Literature reported that between 10 MHZ 1 GHZ frequency range, high electrical conductivity of polyaniline as shielding material, more than 20 db shielding effectiveness can be obtained. High conductive polyaniline thin film thickness of more than 20 um, its shielding effectiveness is greater than 40 db, can satisfy the standard of civil. But conductive polyaniline as electromagnetic shielding material, at present is the key problem of polyanilines conductivity is not high enough. Therefore, improve the conductivity of polyaniline is one of the main research target in the future. (三)聚苯胺在其它方面的应用(3) application of polyaniline in other aspects 在普通纤维中混用极少量的导电聚苯胺纤维，就能赋予纤维制品充分的抗静电性能，而且抗静电性能不会受到环境湿度的影响。聚苯胺的电致变色特性可作为很好的电致变色器，在军事伪装和智能窗等方面有着诱人的前景。麦科技大学用聚苯胺做人造肌肉，虽然目前的使用寿命仅为100次，但有望在将来用于机器人的人造肌肉。由于聚苯胺的光电特性，还可用作光学器件及非线性光学器件。聚苯胺可制作发光二极管，1992年，美国的unix公司报道了柔韧可弯曲的聚合物发光二极管。该二极管的第一层是聚对苯二甲酸乙酯，第二层为聚苯胺薄膜(正电极)，再上面的第三层为发光薄膜和钙膜(负电极)。所制得的二极管在2-3v电压下可发出桔黄色光，使用不同的发光层还可获得不同颜色的光。In ordinary fiber mixed with very small amount