一、硅油是什么
硅油一般是無色(se)(或(huo)(huo)淡黃色(se))、無味、無毒(du)、不(bu)易揮發的(de)(de)液體(ti)。硅(gui)油(you)(you)(you)不(bu)溶(rong)(rong)于(yu)水、甲(jia)醇(chun)、乙(yi)二(er)醇(chun)和(he)2-乙(yi)氧基(ji)乙(yi)醇(chun),可與(yu)苯、二(er)甲(jia)醚、甲(jia)基(ji)乙(yi)基(ji)酮(tong)、四氯化(hua)(hua)(hua)(hua)碳或(huo)(huo)煤(mei)油(you)(you)(you)互(hu)溶(rong)(rong),稍溶(rong)(rong)于(yu)丙酮(tong)、二(er)惡(e)烷(wan)、乙(yi)醇(chun)和(he)丁(ding)醇(chun),易溶(rong)(rong)于(yu)苯、甲(jia)苯、二(er)甲(jia)苯、乙(yi)醚和(he)氯代烷(wan)烴。它具有很小(xiao)的(de)(de)蒸汽壓、較高的(de)(de)閃點(dian)(dian)和(he)燃點(dian)(dian)、較低的(de)(de)凝固點(dian)(dian),可在(zai)-50℃-+180℃溫度(du)范轉內長期使用(yong)。隨著鏈段數n的(de)(de)不(bu)同(tong),分(fen)子量(liang)增(zeng)大(da),粘(zhan)(zhan)度(du)也增(zeng)高,固此硅(gui)油(you)(you)(you)可有各種不(bu)同(tong)的(de)(de)粘(zhan)(zhan)度(du),從0.65厘(li)沲直到上百萬厘(li)沲。如果要(yao)制得低粘(zhan)(zhan)度(du)的(de)(de)硅(gui)油(you)(you)(you),可用(yong)酸性白土作為催化(hua)(hua)(hua)(hua)劑,并在(zai)180℃溫度(du)下(xia)進(jin)行(xing)調聚,或(huo)(huo)用(yong)硫酸作為催化(hua)(hua)(hua)(hua)劑,在(zai)低溫度(du)下(xia)進(jin)行(xing)調聚,生(sheng)產高粘(zhan)(zhan)度(du)硅(gui)油(you)(you)(you)或(huo)(huo)粘(zhan)(zhan)稠(chou)物(wu)可用(yong)堿(jian)性催化(hua)(hua)(hua)(hua)劑。
硅油(you)具有耐(nai)(nai)熱性(xing)、電(dian)(dian)(dian)(dian)(dian)絕緣性(xing)、耐(nai)(nai)候性(xing)、疏水性(xing)、生理(li)惰(duo)性(xing)和較小的(de)(de)表面張(zhang)力,此外還(huan)(huan)具有低的(de)(de)粘溫系數、較高(gao)的(de)(de)抗壓縮(suo)性(xing)、有的(de)(de)品種還(huan)(huan)具有耐(nai)(nai)輻射的(de)(de)性(xing)能。抗剪切(qie)性(xing)強,為一般礦物(wu)油(you)的(de)(de)20倍以上的(de)(de)壓縮(suo)性(xing),是理(li)想的(de)(de)液體彈簧,優異(yi)的(de)(de)電(dian)(dian)(dian)(dian)(dian)氣特(te)性(xing),耐(nai)(nai)擊穿電(dian)(dian)(dian)(dian)(dian)壓高(gao)、耐(nai)(nai)電(dian)(dian)(dian)(dian)(dian)弧、耐(nai)(nai)電(dian)(dian)(dian)(dian)(dian)暈、介(jie)電(dian)(dian)(dian)(dian)(dian)耗(hao)小,還(huan)(huan)具有透光性(xing)好和對人(ren)體無毒害作用(yong)等優點。
二、硅油的主要成分有哪些
硅(gui)(gui)油的主要成(cheng)分是聚(ju)二甲(jia)基(ji)硅(gui)(gui)氧(yang)烷(wan)(wan)(wan)和聚(ju)甲(jia)基(ji)硅(gui)(gui)氧(yang)烷(wan)(wan)(wan)。聚(ju)二甲(jia)基(ji)硅(gui)(gui)氧(yang)烷(wan)(wan)(wan)俗稱(cheng)為(wei)二甲(jia)基(ji)硅(gui)(gui)油,化學(xue)式(shi)為(wei)[(CH3)2SiO]n,結構(gou)簡單(dan),易于合成(cheng)。聚(ju)甲(jia)基(ji)硅(gui)(gui)氧(yang)烷(wan)(wan)(wan)常用的是環(huan)狀四(si)甲(jia)基(ji)環(huan)硅(gui)(gui)氧(yang)烷(wan)(wan)(wan),俗稱(cheng)環(huan)硅(gui)(gui)油,化學(xue)式(shi)為(wei){(CH3)2SiO}n,它的化學(xue)結構(gou)中只有一個硅(gui)(gui)原子帶有兩個甲(jia)基(ji)基(ji)團。
硅油由(you)二甲基二氯硅烷加水(shui)水(shui)解制(zhi)得(de)(de)(de)初縮聚(ju)環(huan)體(ti),環(huan)體(ti)經(jing)裂(lie)解、精(jing)餾制(zhi)得(de)(de)(de)低環(huan)體(ti),然后把環(huan)體(ti)、封頭劑、催化劑放在一(yi)起調(diao)聚(ju)就可得(de)(de)(de)到各(ge)種(zhong)不(bu)同聚(ju)合度的混合物(wu),經(jing)減壓蒸餾除去低沸物(wu)就可制(zhi)得(de)(de)(de)硅油。