硅橡膠是指主(zhu)鏈(lian)由硅(gui)和(he)氧(yang)原(yuan)子交替(ti)構成,硅(gui)原(yuan)子上(shang)通(tong)常連有(you)兩個有(you)機基團(tuan)的(de)(de)(de)(de)橡(xiang)(xiang)膠(jiao)。普通(tong)的(de)(de)(de)(de)硅(gui)橡(xiang)(xiang)膠(jiao)主(zhu)要由含甲基和(he)少量乙烯(xi)基的(de)(de)(de)(de)硅(gui)氧(yang)鏈(lian)節組成。苯(ben)基的(de)(de)(de)(de)引(yin)入(ru)可提高(gao)硅(gui)橡(xiang)(xiang)膠(jiao)的(de)(de)(de)(de)耐高(gao)、低溫性(xing)能(neng)(neng)(neng)(neng),三氟(fu)丙基及(ji)氰(qing)基的(de)(de)(de)(de)引(yin)入(ru)則(ze)可提高(gao)硅(gui)橡(xiang)(xiang)膠(jiao)的(de)(de)(de)(de)耐溫及(ji)耐油性(xing)能(neng)(neng)(neng)(neng)。硅(gui)橡(xiang)(xiang)膠(jiao)耐低溫性(xing)能(neng)(neng)(neng)(neng)良好(hao),一般在(zai)-55℃下仍能(neng)(neng)(neng)(neng)工作(zuo)。引(yin)入(ru)苯(ben)基后,可達(da)-73℃。硅(gui)橡(xiang)(xiang)膠(jiao)的(de)(de)(de)(de)耐熱(re)性(xing)能(neng)(neng)(neng)(neng)也(ye)(ye)很突(tu)(tu)出,在(zai)180℃下可長期工作(zuo),稍(shao)高(gao)于200℃也(ye)(ye)能(neng)(neng)(neng)(neng)承(cheng)受數周或更長時間(jian)仍有(you)彈(dan)性(xing),瞬時可耐300℃以(yi)上(shang)的(de)(de)(de)(de)高(gao)溫。硅(gui)橡(xiang)(xiang)膠(jiao)的(de)(de)(de)(de)透(tou)氣(qi)性(xing)好(hao),氧(yang)氣(qi)透(tou)過率在(zai)合成聚合物(wu)中是較高(gao)的(de)(de)(de)(de)。此(ci)(ci)外,硅(gui)橡(xiang)(xiang)膠(jiao)還(huan)具有(you)生理惰性(xing)、不會導(dao)致(zhi)凝血的(de)(de)(de)(de)突(tu)(tu)出特性(xing),因此(ci)(ci)在(zai)醫用(yong)領域應用(yong)廣泛。
主要(yao)品種
硅橡(xiang)膠分類的方法很(hen)多,通常按固(gu)化
前的(de)形態分(fen)為固體(ti)(ti)(ti)硅(gui)(gui)(gui)橡(xiang)(xiang)(xiang)膠(jiao)(jiao)(jiao)和液體(ti)(ti)(ti)硅(gui)(gui)(gui)橡(xiang)(xiang)(xiang)膠(jiao)(jiao)(jiao);按(an)(an)硫化溫(wen)度分(fen)為室(shi)溫(wen)硫化硅(gui)(gui)(gui)橡(xiang)(xiang)(xiang)膠(jiao)(jiao)(jiao),高溫(wen)硫化硅(gui)(gui)(gui)橡(xiang)(xiang)(xiang)膠(jiao)(jiao)(jiao);按(an)(an)所用單(dan)體(ti)(ti)(ti)的(de)不(bu)(bu)同,可(ke)分(fen)為甲基(ji)乙烯基(ji)硅(gui)(gui)(gui)橡(xiang)(xiang)(xiang)膠(jiao)(jiao)(jiao),甲基(ji)苯基(ji)乙烯基(ji)硅(gui)(gui)(gui)橡(xiang)(xiang)(xiang)膠(jiao)(jiao)(jiao)、氟硅(gui)(gui)(gui),腈硅(gui)(gui)(gui)橡(xiang)(xiang)(xiang)膠(jiao)(jiao)(jiao)等(deng);按(an)(an)性能(neng)和用途的(de)不(bu)(bu)同又(you)可(ke)分(fen)為通(tong)用型(xing)、超耐低(di)溫(wen)型(xing)、超耐高溫(wen)型(xing)、高強力型(xing)、耐油型(xing)、醫用型(xing)等(deng)等(deng)。
發展(zhan)史
硅(gui)(gui)橡膠(jiao)早(zao)期是由美(mei)國(guo)以三(san)氯化鐵為催化劑合成(cheng)的。1945年(nian),硅(gui)(gui)橡膠(jiao)產(chan)(chan)品問世。1948年(nian),采用(yong)高比(bi)表面積的氣(qi)相法白炭黑補強的硅(gui)(gui)橡膠(jiao)研(yan)制成(cheng)功,使(shi)硅(gui)(gui)橡膠(jiao)的性能躍升(sheng)到實(shi)用(yong)階段,奠定(ding)了現代硅(gui)(gui)橡膠(jiao)生(sheng)產(chan)(chan)技術(shu)的基礎。從二(er)甲基二(er)氯硅(gui)(gui)烷(wan)合成(cheng)開始生(sheng)產(chan)(chan)硅(gui)(gui)橡膠(jiao)的國(guo)家有美(mei)國(guo)。俄(e)羅斯、德國(guo)、日本、韓(han)國(guo)和中國(guo)等(deng)。中國(guo)硅(gui)(gui)橡膠(jiao)的工業化研(yan)究(jiu)始于1957年(nian),多家研(yan)究(jiu)所和企業陸(lu)續開發出各種硅(gui)(gui)橡膠(jiao)。到2003年(nian)底(di),中國(guo)硅(gui)(gui)橡膠(jiao)生(sheng)產(chan)(chan)能力為135千噸(dun)(dun),其(qi)中高溫膠(jiao)100千噸(dun)(dun)。
高(gao)溫(wen)硫化硅橡膠(jiao)
高(gao)溫(wen)硫(liu)化(hua)硅(gui)橡膠(jiao)(jiao)是指聚(ju)(ju)硅(gui)氧烷(wan)變成彈(dan)性(xing)體的過程是經過高(gao)溫(wen)(110-170℃)硫(liu)化(hua)成型(xing)的。它主(zhu)要以高(gao)分(fen)子量的聚(ju)(ju)甲基乙烯基硅(gui)氧烷(wan)為(wei)生膠(jiao)(jiao),混入補(bu)強填料、硫(liu)化(hua)劑(ji)等,在加(jia)(jia)熱加(jia)(jia)壓下硫(liu)化(hua)成彈(dan)性(xing)體。硅(gui)橡膠(jiao)(jiao)的補(bu)強主(zhu)要是各(ge)種(zhong)類型(xing)的白炭(tan)黑,可(ke)使(shi)硫(liu)化(hua)膠(jiao)(jiao)的強度增加(jia)(jia)數十(shi)倍。有(you)時為(wei)了降低成本或(huo)改善(shan)膠(jiao)(jiao)料性(xing)能(neng)及賦予硫(liu)化(hua)膠(jiao)(jiao)各(ge)種(zhong)特殊的性(xing)能(neng),也加(jia)(jia)入相應的各(ge)種(zhong)添加(jia)(jia)劑(ji)。硫(liu)化(hua)劑(ji)是各(ge)種(zhong)有(you)機過氧化(hua)物或(huo)加(jia)(jia)成反應催化(hua)劑(ji)。
加工(gong)成型方法(fa)如圖所示(shi)。一次硫化的目的是進行(xing)(xing)高分子鏈的交(jiao)聯反應;二次硫化的目的是進行(xing)(xing)補充(chong)交(jiao)聯、驅(qu)除(chu)硫化劑分解(jie)產物和其(qi)他(ta)揮發性(xing)化合(he)物以穩定硫化膠的各(ge)項性(xing)能(neng)。常用(yong)的設備(bei)有開放式煉(lian)膠機(ji)、捏合(he)機(ji)及真空密(mi)煉(lian)機(ji)。
主要性能
(1)高(gao)溫(wen)(wen)性(xing)(xing)(xing)(xing)(xing)(xing)能(neng)。硅(gui)(gui)(gui)橡(xiang)膠顯(xian)著的(de)(de)特征是高(gao)溫(wen)(wen)穩定(ding)(ding)性(xing)(xing)(xing)(xing)(xing)(xing),雖(sui)然(ran)常(chang)溫(wen)(wen)下(xia)(xia)硅(gui)(gui)(gui)橡(xiang)膠的(de)(de)強度僅是天然(ran)橡(xiang)膠或某(mou)些合成橡(xiang)膠的(de)(de)一半,但(dan)(dan)在200℃以上的(de)(de)高(gao)溫(wen)(wen)環境(jing)下(xia)(xia),硅(gui)(gui)(gui)橡(xiang)膠仍(reng)能(neng)保(bao)持(chi)一定(ding)(ding)的(de)(de)柔韌性(xing)(xing)(xing)(xing)(xing)(xing)、回(hui)彈性(xing)(xing)(xing)(xing)(xing)(xing)和表面硬度,且力(li)學性(xing)(xing)(xing)(xing)(xing)(xing)能(neng)無(wu)明顯(xian)變化(hua)(hua)。(2)低溫(wen)(wen)性(xing)(xing)(xing)(xing)(xing)(xing)能(neng)硅(gui)(gui)(gui)橡(xiang)膠的(de)(de)玻(bo)璃化(hua)(hua)溫(wen)(wen)度一般為-70~-50℃,特殊(shu)配方可達-100℃,表明其低溫(wen)(wen)性(xing)(xing)(xing)(xing)(xing)(xing)能(neng)優(you)異。這對(dui)航(hang)空、宇航(hang)工業的(de)(de)意(yi)義重大(da)。(3)耐候性(xing)(xing)(xing)(xing)(xing)(xing)硅(gui)(gui)(gui)橡(xiang)膠中Si-O-Si鍵(jian)對(dui)氧、臭氧及紫外線等十分(fen)穩定(ding)(ding),在不(bu)加(jia)任何(he)添加(jia)劑(ji)的(de)(de)情況下(xia)(xia),就具(ju)有優(you)良的(de)(de)耐候性(xing)(xing)(xing)(xing)(xing)(xing)。(4)電氣(qi)性(xing)(xing)(xing)(xing)(xing)(xing)能(neng)。硅(gui)(gui)(gui)橡(xiang)膠具(ju)有優(you)異的(de)(de)絕緣性(xing)(xing)(xing)(xing)(xing)(xing)能(neng),耐電暈性(xing)(xing)(xing)(xing)(xing)(xing)和耐電弧性(xing)(xing)(xing)(xing)(xing)(xing)也非常(chang)好。(5)物(wu)理機(ji)械(xie)性(xing)(xing)(xing)(xing)(xing)(xing)能(neng)。硅(gui)(gui)(gui)橡(xiang)膠常(chang)溫(wen)(wen)下(xia)(xia)的(de)(de)物(wu)理機(ji)械(xie)性(xing)(xing)(xing)(xing)(xing)(xing)能(neng)比通(tong)(tong)用橡(xiang)膠差,但(dan)(dan)在150℃的(de)(de)高(gao)溫(wen)(wen)和-50℃的(de)(de)低溫(wen)(wen)下(xia)(xia),其物(wu)理機(ji)械(xie)性(xing)(xing)(xing)(xing)(xing)(xing)能(neng)優(you)于通(tong)(tong)用橡(xiang)膠。(6)耐油及化(hua)(hua)學試劑(ji)性(xing)(xing)(xing)(xing)(xing)(xing)。普通(tong)(tong)硅(gui)(gui)(gui)橡(xiang)膠具(ju)有中等的(de)(de)耐油、耐溶劑(ji)性(xing)(xing)(xing)(xing)(xing)(xing)能(neng)。(7)氣(qi)體透過性(xing)(xing)(xing)(xing)(xing)(xing)能(neng)。室溫(wen)(wen)下(xia)(xia)硅(gui)(gui)(gui)橡(xiang)膠對(dui)空氣(qi)、氮、氧、二氧化(hua)(hua)碳等氣(qi)體的(de)(de)透氣(qi)性(xing)(xing)(xing)(xing)(xing)(xing)比天然(ran)橡(xiang)膠高(gao)出30-50倍。(8)生(sheng)理惰性(xing)(xing)(xing)(xing)(xing)(xing)。硅(gui)(gui)(gui)橡(xiang)膠無(wu)毒,無(wu)味,無(wu)嗅,與人(ren)體組(zu)織不(bu)粘連,具(ju)有抗凝血(xue)作(zuo)用,對(dui)肌體組(zu)織的(de)(de)反應性(xing)(xing)(xing)(xing)(xing)(xing)非常(chang)少。特別適合作(zuo)為醫用材(cai)料。
硅橡膠的用(yong)量(liang)
據中國(guo)(guo)汽(qi)(qi)(qi)車工(gong)(gong)業(ye)協會(hui)統計,2012年,汽(qi)(qi)(qi)車產銷分別達(da)到1927.18萬(wan)(wan)輛和(he)(he)1930.64萬(wan)(wan)輛,同比分別增(zeng)長(chang)4.63%和(he)(he)4.33%,汽(qi)(qi)(qi)車工(gong)(gong)業(ye)硅橡膠的(de)用(yong)(yong)量(liang)(liang)約(yue)達(da)2.0萬(wan)(wan)t。根據觀研(yan)天下(xia)的(de)新研(yan)究,增(zeng)加有(you)機(ji)(ji)硅材料在汽(qi)(qi)(qi)車零(ling)部(bu)件方面的(de)用(yong)(yong)量(liang)(liang),可以(yi)大幅(fu)度提(ti)(ti)(ti)高汽(qi)(qi)(qi)車的(de)安全性能,因(yin)此,汽(qi)(qi)(qi)車產量(liang)(liang)和(he)(he)單車用(yong)(yong)量(liang)(liang)水平(ping)的(de)提(ti)(ti)(ti)高都將推動汽(qi)(qi)(qi)車工(gong)(gong)業(ye)對硅橡膠需求的(de)增(zeng)加。國(guo)(guo)家(jia)鼓勵自(zi)(zi)主(zhu)品(pin)牌(pai)的(de)汽(qi)(qi)(qi)車發展(zhan)(zhan),關(guan)鍵汽(qi)(qi)(qi)車零(ling)部(bu)件實(shi)現自(zi)(zi)主(zhu)化(hua),《2012年度黨(dang)政(zheng)機(ji)(ji)關(guan)公(gong)務(wu)用(yong)(yong)車選用(yong)(yong)車型目錄(征求意見稿)》為自(zi)(zi)主(zhu)品(pin)牌(pai)擴大在政(zheng)府(fu)(fu)采(cai)購(gou)(gou)的(de)市場份額(e),為改變目前國(guo)(guo)內政(zheng)府(fu)(fu)采(cai)購(gou)(gou)以(yi)合資(zi)品(pin)牌(pai)產品(pin)為主(zhu)的(de)局面提(ti)(ti)(ti)供了保障(zhang)。促進自(zi)(zi)主(zhu)品(pin)牌(pai)發展(zhan)(zhan),國(guo)(guo)產汽(qi)(qi)(qi)車業(ye)的(de)繁榮將為汽(qi)(qi)(qi)車膠的(de)應用(yong)(yong)提(ti)(ti)(ti)供有(you)力保障(zhang)。預測未來3年,我國(guo)(guo)室溫(wen)硫化(hua)硅橡膠在汽(qi)(qi)(qi)車行業(ye)將以(yi)年均20%增(zeng)長(chang)。
此外,硅(gui)橡(xiang)(xiang)膠(jiao)(jiao)(jiao)是重(zhong)要的(de)非石(shi)(shi)油(you)基合(he)(he)(he)成(cheng)橡(xiang)(xiang)膠(jiao)(jiao)(jiao),約(yue)占(zhan)非石(shi)(shi)油(you)基合(he)(he)(he)成(cheng)橡(xiang)(xiang)膠(jiao)(jiao)(jiao)消費量的(de)98%。但因為(wei)(wei)石(shi)(shi)油(you)價格的(de)大(da)幅上漲,同時我(wo)國(guo)在(zai)硅(gui)橡(xiang)(xiang)膠(jiao)(jiao)(jiao)的(de)關(guan)鍵原料有機(ji)硅(gui)單(dan)體的(de)生(sheng)(sheng)產(chan)技術方面取得突破,有機(ji)硅(gui)單(dan)體的(de)生(sheng)(sheng)產(chan)技術在(zai)2005年前被幾家跨國(guo)公司壟斷,但目前我(wo)國(guo)已發(fa)展成(cheng)為(wei)(wei)全球(qiu)有機(ji)硅(gui)單(dan)體第1大(da)國(guo),這(zhe)2個方面原因使(shi)硅(gui)橡(xiang)(xiang)膠(jiao)(jiao)(jiao)的(de)價格從(cong)2011年起開始低于石(shi)(shi)油(you)基合(he)(he)(he)成(cheng)橡(xiang)(xiang)膠(jiao)(jiao)(jiao),僅(jin)約(yue)為(wei)(wei)大(da)宗(zong)石(shi)(shi)油(you)基橡(xiang)(xiang)膠(jiao)(jiao)(jiao)的(de)80%~90%,成(cheng)為(wei)(wei)廉價的(de)合(he)(he)(he)成(cheng)橡(xiang)(xiang)膠(jiao)(jiao)(jiao),并開始大(da)規模替代石(shi)(shi)油(you)基合(he)(he)(he)成(cheng)橡(xiang)(xiang)膠(jiao)(jiao)(jiao)。這(zhe)將極大(da)拓展有機(ji)硅(gui)產(chan)業的(de)市場(chang)空(kong)間,同時將帶動硅(gui)油(you)、硅(gui)烷偶聯劑(ji)和硅(gui)樹脂等其他有機(ji)硅(gui)產(chan)品的(de)消費。