硅橡膠是指主(zhu)鏈(lian)由硅和氧(yang)原子交(jiao)替構成(cheng)(cheng),硅原子上(shang)通(tong)常連有兩(liang)個有機基(ji)(ji)團(tuan)的(de)(de)橡(xiang)(xiang)(xiang)膠(jiao)。普通(tong)的(de)(de)硅橡(xiang)(xiang)(xiang)膠(jiao)主(zhu)要由含甲基(ji)(ji)和少量乙(yi)烯基(ji)(ji)的(de)(de)硅氧(yang)鏈(lian)節組(zu)成(cheng)(cheng)。苯(ben)基(ji)(ji)的(de)(de)引入(ru)可(ke)提(ti)高(gao)(gao)硅橡(xiang)(xiang)(xiang)膠(jiao)的(de)(de)耐高(gao)(gao)、低(di)(di)溫性(xing)能(neng),三氟(fu)丙基(ji)(ji)及氰基(ji)(ji)的(de)(de)引入(ru)則可(ke)提(ti)高(gao)(gao)硅橡(xiang)(xiang)(xiang)膠(jiao)的(de)(de)耐溫及耐油(you)性(xing)能(neng)。硅橡(xiang)(xiang)(xiang)膠(jiao)耐低(di)(di)溫性(xing)能(neng)良(liang)好,一(yi)般(ban)在(zai)-55℃下(xia)仍(reng)能(neng)工(gong)(gong)作。引入(ru)苯(ben)基(ji)(ji)后,可(ke)達-73℃。硅橡(xiang)(xiang)(xiang)膠(jiao)的(de)(de)耐熱性(xing)能(neng)也很(hen)突出(chu),在(zai)180℃下(xia)可(ke)長(chang)期工(gong)(gong)作,稍高(gao)(gao)于200℃也能(neng)承受數周或更長(chang)時間仍(reng)有彈性(xing),瞬時可(ke)耐300℃以(yi)上(shang)的(de)(de)高(gao)(gao)溫。硅橡(xiang)(xiang)(xiang)膠(jiao)的(de)(de)透氣(qi)性(xing)好,氧(yang)氣(qi)透過率在(zai)合成(cheng)(cheng)聚合物中(zhong)是較(jiao)高(gao)(gao)的(de)(de)。此外,硅橡(xiang)(xiang)(xiang)膠(jiao)還具有生理惰性(xing)、不會導致凝血的(de)(de)突出(chu)特性(xing),因此在(zai)醫(yi)用領(ling)域(yu)應用廣(guang)泛(fan)。
主要品種
硅(gui)橡(xiang)(xiang)(xiang)膠分(fen)(fen)類(lei)的(de)(de)(de)方法很多,通常按固(gu)化(hua)前的(de)(de)(de)形(xing)態分(fen)(fen)為固(gu)體硅(gui)橡(xiang)(xiang)(xiang)膠和液體硅(gui)橡(xiang)(xiang)(xiang)膠;按硫(liu)化(hua)溫(wen)度分(fen)(fen)為室溫(wen)硫(liu)化(hua)硅(gui)橡(xiang)(xiang)(xiang)膠,高(gao)溫(wen)硫(liu)化(hua)硅(gui)橡(xiang)(xiang)(xiang)膠;按所用單(dan)體的(de)(de)(de)不(bu)(bu)同,可分(fen)(fen)為甲基(ji)乙烯基(ji)硅(gui)橡(xiang)(xiang)(xiang)膠,甲基(ji)苯基(ji)乙烯基(ji)硅(gui)橡(xiang)(xiang)(xiang)膠、氟(fu)硅(gui),腈硅(gui)橡(xiang)(xiang)(xiang)膠等(deng)(deng);按性能和用途的(de)(de)(de)不(bu)(bu)同又可分(fen)(fen)為通用型(xing)(xing)、超(chao)耐低溫(wen)型(xing)(xing)、超(chao)耐高(gao)溫(wen)型(xing)(xing)、高(gao)強力型(xing)(xing)、耐油(you)型(xing)(xing)、醫用型(xing)(xing)等(deng)(deng)等(deng)(deng)。
發展史
硅(gui)(gui)橡(xiang)膠(jiao)(jiao)早期是由美國以三(san)氯化(hua)(hua)鐵(tie)為催(cui)化(hua)(hua)劑合(he)成的(de)。1945年(nian)(nian)(nian),硅(gui)(gui)橡(xiang)膠(jiao)(jiao)產(chan)品問(wen)世。1948年(nian)(nian)(nian),采用(yong)高比表面積的(de)氣相法白(bai)炭黑補強(qiang)的(de)硅(gui)(gui)橡(xiang)膠(jiao)(jiao)研(yan)制(zhi)成功,使硅(gui)(gui)橡(xiang)膠(jiao)(jiao)的(de)性能躍升(sheng)到(dao)實用(yong)階段,奠定了現代(dai)硅(gui)(gui)橡(xiang)膠(jiao)(jiao)生產(chan)技術的(de)基(ji)礎。從二甲基(ji)二氯硅(gui)(gui)烷合(he)成開(kai)始生產(chan)硅(gui)(gui)橡(xiang)膠(jiao)(jiao)的(de)國家有美國。俄羅斯(si)、德國、日(ri)本、韓國和中(zhong)(zhong)國等。中(zhong)(zhong)國硅(gui)(gui)橡(xiang)膠(jiao)(jiao)的(de)工業化(hua)(hua)研(yan)究始于1957年(nian)(nian)(nian),多家研(yan)究所和企業陸續開(kai)發出(chu)各種硅(gui)(gui)橡(xiang)膠(jiao)(jiao)。到(dao)2003年(nian)(nian)(nian)底,中(zhong)(zhong)國硅(gui)(gui)橡(xiang)膠(jiao)(jiao)生產(chan)能力(li)為135千噸(dun),其中(zhong)(zhong)高溫膠(jiao)(jiao)100千噸(dun)。
高溫硫化硅橡膠
高(gao)(gao)溫硫(liu)化(hua)硅(gui)橡膠(jiao)是(shi)指聚(ju)(ju)硅(gui)氧(yang)(yang)烷變成(cheng)(cheng)彈性(xing)體(ti)的(de)(de)(de)過程是(shi)經過高(gao)(gao)溫(110-170℃)硫(liu)化(hua)成(cheng)(cheng)型的(de)(de)(de)。它主要(yao)以高(gao)(gao)分子量的(de)(de)(de)聚(ju)(ju)甲基乙烯基硅(gui)氧(yang)(yang)烷為生膠(jiao),混入補(bu)(bu)強(qiang)(qiang)填(tian)料、硫(liu)化(hua)劑等,在加(jia)(jia)熱加(jia)(jia)壓下硫(liu)化(hua)成(cheng)(cheng)彈性(xing)體(ti)。硅(gui)橡膠(jiao)的(de)(de)(de)補(bu)(bu)強(qiang)(qiang)主要(yao)是(shi)各(ge)(ge)種(zhong)類型的(de)(de)(de)白炭(tan)黑,可使硫(liu)化(hua)膠(jiao)的(de)(de)(de)強(qiang)(qiang)度增加(jia)(jia)數十(shi)倍。有時為了降低成(cheng)(cheng)本或(huo)改善膠(jiao)料性(xing)能及賦予硫(liu)化(hua)膠(jiao)各(ge)(ge)種(zhong)特殊的(de)(de)(de)性(xing)能,也加(jia)(jia)入相應的(de)(de)(de)各(ge)(ge)種(zhong)添加(jia)(jia)劑。硫(liu)化(hua)劑是(shi)各(ge)(ge)種(zhong)有機過氧(yang)(yang)化(hua)物(wu)或(huo)加(jia)(jia)成(cheng)(cheng)反應催化(hua)劑。
加工(gong)成型方法如圖所示。一次硫(liu)化的(de)(de)目的(de)(de)是進行(xing)高(gao)分子鏈的(de)(de)交聯反應;二次硫(liu)化的(de)(de)目的(de)(de)是進行(xing)補充交聯、驅除硫(liu)化劑分解產(chan)物和其他揮發性(xing)(xing)化合物以(yi)穩定(ding)硫(liu)化膠的(de)(de)各項性(xing)(xing)能。常用的(de)(de)設備有(you)開放式(shi)煉膠機(ji)、捏合機(ji)及真空密煉機(ji)。
主要性能
(1)高(gao)溫性(xing)(xing)(xing)(xing)(xing)能(neng)(neng)(neng)(neng)(neng)。硅(gui)(gui)橡(xiang)(xiang)(xiang)(xiang)(xiang)膠顯著的(de)(de)(de)特(te)征是高(gao)溫穩定性(xing)(xing)(xing)(xing)(xing),雖然(ran)常溫下(xia)硅(gui)(gui)橡(xiang)(xiang)(xiang)(xiang)(xiang)膠的(de)(de)(de)強度僅是天然(ran)橡(xiang)(xiang)(xiang)(xiang)(xiang)膠或某(mou)些(xie)合(he)成橡(xiang)(xiang)(xiang)(xiang)(xiang)膠的(de)(de)(de)一(yi)半,但在(zai)(zai)200℃以上的(de)(de)(de)高(gao)溫環境下(xia),硅(gui)(gui)橡(xiang)(xiang)(xiang)(xiang)(xiang)膠仍能(neng)(neng)(neng)(neng)(neng)保持一(yi)定的(de)(de)(de)柔韌性(xing)(xing)(xing)(xing)(xing)、回彈性(xing)(xing)(xing)(xing)(xing)和(he)表(biao)面(mian)硬度,且力學性(xing)(xing)(xing)(xing)(xing)能(neng)(neng)(neng)(neng)(neng)無(wu)(wu)明顯變(bian)化。(2)低溫性(xing)(xing)(xing)(xing)(xing)能(neng)(neng)(neng)(neng)(neng)硅(gui)(gui)橡(xiang)(xiang)(xiang)(xiang)(xiang)膠的(de)(de)(de)玻璃化溫度一(yi)般為(wei)-70~-50℃,特(te)殊(shu)配方可(ke)達(da)-100℃,表(biao)明其低溫性(xing)(xing)(xing)(xing)(xing)能(neng)(neng)(neng)(neng)(neng)優異。這(zhe)對航空、宇航工(gong)業的(de)(de)(de)意義(yi)重(zhong)大。(3)耐(nai)(nai)候性(xing)(xing)(xing)(xing)(xing)硅(gui)(gui)橡(xiang)(xiang)(xiang)(xiang)(xiang)膠中(zhong)(zhong)Si-O-Si鍵對氧、臭氧及紫外線等十(shi)分穩定,在(zai)(zai)不(bu)加(jia)任(ren)何添加(jia)劑的(de)(de)(de)情況下(xia),就具(ju)有(you)優良的(de)(de)(de)耐(nai)(nai)候性(xing)(xing)(xing)(xing)(xing)。(4)電(dian)氣性(xing)(xing)(xing)(xing)(xing)能(neng)(neng)(neng)(neng)(neng)。硅(gui)(gui)橡(xiang)(xiang)(xiang)(xiang)(xiang)膠具(ju)有(you)優異的(de)(de)(de)絕緣性(xing)(xing)(xing)(xing)(xing)能(neng)(neng)(neng)(neng)(neng),耐(nai)(nai)電(dian)暈性(xing)(xing)(xing)(xing)(xing)和(he)耐(nai)(nai)電(dian)弧性(xing)(xing)(xing)(xing)(xing)也非常好。(5)物理機械性(xing)(xing)(xing)(xing)(xing)能(neng)(neng)(neng)(neng)(neng)。硅(gui)(gui)橡(xiang)(xiang)(xiang)(xiang)(xiang)膠常溫下(xia)的(de)(de)(de)物理機械性(xing)(xing)(xing)(xing)(xing)能(neng)(neng)(neng)(neng)(neng)比(bi)通(tong)(tong)用(yong)橡(xiang)(xiang)(xiang)(xiang)(xiang)膠差,但在(zai)(zai)150℃的(de)(de)(de)高(gao)溫和(he)-50℃的(de)(de)(de)低溫下(xia),其物理機械性(xing)(xing)(xing)(xing)(xing)能(neng)(neng)(neng)(neng)(neng)優于通(tong)(tong)用(yong)橡(xiang)(xiang)(xiang)(xiang)(xiang)膠。(6)耐(nai)(nai)油及化學試(shi)劑性(xing)(xing)(xing)(xing)(xing)。普通(tong)(tong)硅(gui)(gui)橡(xiang)(xiang)(xiang)(xiang)(xiang)膠具(ju)有(you)中(zhong)(zhong)等的(de)(de)(de)耐(nai)(nai)油、耐(nai)(nai)溶劑性(xing)(xing)(xing)(xing)(xing)能(neng)(neng)(neng)(neng)(neng)。(7)氣體透(tou)(tou)過性(xing)(xing)(xing)(xing)(xing)能(neng)(neng)(neng)(neng)(neng)。室(shi)溫下(xia)硅(gui)(gui)橡(xiang)(xiang)(xiang)(xiang)(xiang)膠對空氣、氮、氧、二(er)氧化碳等氣體的(de)(de)(de)透(tou)(tou)氣性(xing)(xing)(xing)(xing)(xing)比(bi)天然(ran)橡(xiang)(xiang)(xiang)(xiang)(xiang)膠高(gao)出30-50倍。(8)生理惰性(xing)(xing)(xing)(xing)(xing)。硅(gui)(gui)橡(xiang)(xiang)(xiang)(xiang)(xiang)膠無(wu)(wu)毒,無(wu)(wu)味,無(wu)(wu)嗅(xiu),與人體組織不(bu)粘連,具(ju)有(you)抗凝血作用(yong),對肌體組織的(de)(de)(de)反(fan)應(ying)性(xing)(xing)(xing)(xing)(xing)非常少(shao)。特(te)別適合(he)作為(wei)醫用(yong)材料。
硅橡膠的用量
據中國汽(qi)(qi)車(che)(che)(che)工(gong)業(ye)協會統計,2012年(nian),汽(qi)(qi)車(che)(che)(che)產(chan)銷分別達到1927.18萬(wan)(wan)輛和1930.64萬(wan)(wan)輛,同比分別增(zeng)長(chang)4.63%和4.33%,汽(qi)(qi)車(che)(che)(che)工(gong)業(ye)硅(gui)橡膠(jiao)的用(yong)(yong)量(liang)約達2.0萬(wan)(wan)t。根據觀研(yan)(yan)天下的新研(yan)(yan)究,增(zeng)加(jia)有機(ji)硅(gui)材(cai)料在(zai)汽(qi)(qi)車(che)(che)(che)零部(bu)件方(fang)面的用(yong)(yong)量(liang),可(ke)以大(da)幅度(du)提(ti)高汽(qi)(qi)車(che)(che)(che)的安全性能,因此,汽(qi)(qi)車(che)(che)(che)產(chan)量(liang)和單(dan)車(che)(che)(che)用(yong)(yong)量(liang)水平的提(ti)高都將(jiang)推動汽(qi)(qi)車(che)(che)(che)工(gong)業(ye)對(dui)硅(gui)橡膠(jiao)需求的增(zeng)加(jia)。國家鼓勵自(zi)主(zhu)品(pin)牌(pai)(pai)的汽(qi)(qi)車(che)(che)(che)發展(zhan),關鍵汽(qi)(qi)車(che)(che)(che)零部(bu)件實現自(zi)主(zhu)化(hua),《2012年(nian)度(du)黨(dang)政(zheng)機(ji)關公務用(yong)(yong)車(che)(che)(che)選用(yong)(yong)車(che)(che)(che)型目錄(征(zheng)求意(yi)見稿)》為(wei)自(zi)主(zhu)品(pin)牌(pai)(pai)擴(kuo)大(da)在(zai)政(zheng)府采購的市場份額(e),為(wei)改變(bian)目前國內政(zheng)府采購以合資品(pin)牌(pai)(pai)產(chan)品(pin)為(wei)主(zhu)的局面提(ti)供(gong)了保障。促進自(zi)主(zhu)品(pin)牌(pai)(pai)發展(zhan),國產(chan)汽(qi)(qi)車(che)(che)(che)業(ye)的繁(fan)榮將(jiang)為(wei)汽(qi)(qi)車(che)(che)(che)膠(jiao)的應用(yong)(yong)提(ti)供(gong)有力保障。預(yu)測未來3年(nian),我國室溫硫(liu)化(hua)硅(gui)橡膠(jiao)在(zai)汽(qi)(qi)車(che)(che)(che)行業(ye)將(jiang)以年(nian)均20%增(zeng)長(chang)。
此(ci)外,硅(gui)橡(xiang)(xiang)膠是重要(yao)的非(fei)石(shi)(shi)油基合(he)成(cheng)(cheng)(cheng)(cheng)橡(xiang)(xiang)膠,約占非(fei)石(shi)(shi)油基合(he)成(cheng)(cheng)(cheng)(cheng)橡(xiang)(xiang)膠消費(fei)量的98%。但因(yin)為(wei)石(shi)(shi)油價(jia)(jia)格(ge)的大(da)幅上漲(zhang),同時(shi)(shi)我國在硅(gui)橡(xiang)(xiang)膠的關鍵原料有(you)(you)機(ji)硅(gui)單體(ti)的生產技(ji)術方(fang)面取(qu)得突破(po),有(you)(you)機(ji)硅(gui)單體(ti)的生產技(ji)術在2005年前(qian)被幾家跨國公司壟斷(duan),但目前(qian)我國已發展(zhan)成(cheng)(cheng)(cheng)(cheng)為(wei)全球有(you)(you)機(ji)硅(gui)單體(ti)第(di)1大(da)國,這2個(ge)方(fang)面原因(yin)使硅(gui)橡(xiang)(xiang)膠的價(jia)(jia)格(ge)從(cong)2011年起開(kai)始低(di)于石(shi)(shi)油基合(he)成(cheng)(cheng)(cheng)(cheng)橡(xiang)(xiang)膠,僅約為(wei)大(da)宗石(shi)(shi)油基橡(xiang)(xiang)膠的80%~90%,成(cheng)(cheng)(cheng)(cheng)為(wei)廉價(jia)(jia)的合(he)成(cheng)(cheng)(cheng)(cheng)橡(xiang)(xiang)膠,并開(kai)始大(da)規模(mo)替代石(shi)(shi)油基合(he)成(cheng)(cheng)(cheng)(cheng)橡(xiang)(xiang)膠。這將極大(da)拓展(zhan)有(you)(you)機(ji)硅(gui)產業(ye)的市場空間,同時(shi)(shi)將帶(dai)動硅(gui)油、硅(gui)烷偶聯劑和硅(gui)樹脂等其(qi)他有(you)(you)機(ji)硅(gui)產品(pin)的消費(fei)。