硅橡膠是指主(zhu)鏈由(you)硅(gui)和氧(yang)原(yuan)子交替構成(cheng)(cheng)(cheng),硅(gui)原(yuan)子上通(tong)常連有兩個有機基(ji)團(tuan)的(de)(de)(de)橡(xiang)膠(jiao)。普通(tong)的(de)(de)(de)硅(gui)橡(xiang)膠(jiao)主(zhu)要由(you)含甲基(ji)和少量乙烯基(ji)的(de)(de)(de)硅(gui)氧(yang)鏈節組成(cheng)(cheng)(cheng)。苯(ben)基(ji)的(de)(de)(de)引(yin)入(ru)(ru)(ru)可(ke)提(ti)高硅(gui)橡(xiang)膠(jiao)的(de)(de)(de)耐(nai)高、低溫(wen)(wen)性(xing)(xing)能(neng)(neng),三氟丙基(ji)及氰基(ji)的(de)(de)(de)引(yin)入(ru)(ru)(ru)則可(ke)提(ti)高硅(gui)橡(xiang)膠(jiao)的(de)(de)(de)耐(nai)溫(wen)(wen)及耐(nai)油性(xing)(xing)能(neng)(neng)。硅(gui)橡(xiang)膠(jiao)耐(nai)低溫(wen)(wen)性(xing)(xing)能(neng)(neng)良好,一般在-55℃下(xia)仍(reng)能(neng)(neng)工作。引(yin)入(ru)(ru)(ru)苯(ben)基(ji)后,可(ke)達-73℃。硅(gui)橡(xiang)膠(jiao)的(de)(de)(de)耐(nai)熱性(xing)(xing)能(neng)(neng)也很突(tu)出,在180℃下(xia)可(ke)長期(qi)工作,稍高于200℃也能(neng)(neng)承受數周(zhou)或(huo)更長時間仍(reng)有彈性(xing)(xing),瞬時可(ke)耐(nai)300℃以上的(de)(de)(de)高溫(wen)(wen)。硅(gui)橡(xiang)膠(jiao)的(de)(de)(de)透氣(qi)性(xing)(xing)好,氧(yang)氣(qi)透過率在合成(cheng)(cheng)(cheng)聚(ju)合物(wu)中是較高的(de)(de)(de)。此(ci)外,硅(gui)橡(xiang)膠(jiao)還(huan)具有生理惰性(xing)(xing)、不會導致(zhi)凝(ning)血的(de)(de)(de)突(tu)出特性(xing)(xing),因此(ci)在醫(yi)用(yong)領(ling)域應用(yong)廣泛。
主要品種
硅橡膠分類的方法很(hen)多,通常按固(gu)化(hua)
前的(de)形態分(fen)為(wei)(wei)固體(ti)硅(gui)(gui)(gui)(gui)橡(xiang)膠(jiao)(jiao)(jiao)和(he)液體(ti)硅(gui)(gui)(gui)(gui)橡(xiang)膠(jiao)(jiao)(jiao);按硫化(hua)(hua)溫度分(fen)為(wei)(wei)室(shi)溫硫化(hua)(hua)硅(gui)(gui)(gui)(gui)橡(xiang)膠(jiao)(jiao)(jiao),高(gao)溫硫化(hua)(hua)硅(gui)(gui)(gui)(gui)橡(xiang)膠(jiao)(jiao)(jiao);按所用(yong)單體(ti)的(de)不同,可分(fen)為(wei)(wei)甲基乙烯基硅(gui)(gui)(gui)(gui)橡(xiang)膠(jiao)(jiao)(jiao),甲基苯(ben)基乙烯基硅(gui)(gui)(gui)(gui)橡(xiang)膠(jiao)(jiao)(jiao)、氟硅(gui)(gui)(gui)(gui),腈(jing)硅(gui)(gui)(gui)(gui)橡(xiang)膠(jiao)(jiao)(jiao)等;按性能和(he)用(yong)途的(de)不同又可分(fen)為(wei)(wei)通用(yong)型(xing)、超耐(nai)低溫型(xing)、超耐(nai)高(gao)溫型(xing)、高(gao)強力型(xing)、耐(nai)油型(xing)、醫用(yong)型(xing)等等。
發(fa)展史(shi)
硅橡(xiang)(xiang)膠(jiao)早期(qi)是由(you)美(mei)國(guo)以三氯化(hua)鐵為(wei)催(cui)化(hua)劑合成(cheng)的(de)(de)。1945年,硅橡(xiang)(xiang)膠(jiao)產(chan)品(pin)問(wen)世。1948年,采用高比表(biao)面積的(de)(de)氣相法白炭(tan)黑補強的(de)(de)硅橡(xiang)(xiang)膠(jiao)研制(zhi)成(cheng)功,使硅橡(xiang)(xiang)膠(jiao)的(de)(de)性能(neng)躍升到(dao)實(shi)用階段,奠定了現代(dai)硅橡(xiang)(xiang)膠(jiao)生(sheng)產(chan)技術的(de)(de)基礎。從二甲基二氯硅烷合成(cheng)開(kai)始(shi)生(sheng)產(chan)硅橡(xiang)(xiang)膠(jiao)的(de)(de)國(guo)家(jia)有美(mei)國(guo)。俄羅(luo)斯(si)、德國(guo)、日本(ben)、韓國(guo)和(he)中(zhong)國(guo)等。中(zhong)國(guo)硅橡(xiang)(xiang)膠(jiao)的(de)(de)工(gong)業化(hua)研究始(shi)于(yu)1957年,多家(jia)研究所(suo)和(he)企業陸續開(kai)發(fa)出各種(zhong)硅橡(xiang)(xiang)膠(jiao)。到(dao)2003年底,中(zhong)國(guo)硅橡(xiang)(xiang)膠(jiao)生(sheng)產(chan)能(neng)力(li)為(wei)135千噸(dun),其(qi)中(zhong)高溫(wen)膠(jiao)100千噸(dun)。
高溫硫化硅橡膠
高(gao)溫硫化(hua)(hua)(hua)硅橡(xiang)膠(jiao)(jiao)是指聚硅氧烷(wan)變成(cheng)彈(dan)性(xing)體(ti)的過(guo)程(cheng)是經過(guo)高(gao)溫(110-170℃)硫化(hua)(hua)(hua)成(cheng)型(xing)的。它(ta)主(zhu)(zhu)要以高(gao)分子量的聚甲基乙(yi)烯基硅氧烷(wan)為生膠(jiao)(jiao),混入補強填(tian)料、硫化(hua)(hua)(hua)劑等,在(zai)加(jia)(jia)熱加(jia)(jia)壓下硫化(hua)(hua)(hua)成(cheng)彈(dan)性(xing)體(ti)。硅橡(xiang)膠(jiao)(jiao)的補強主(zhu)(zhu)要是各(ge)種(zhong)(zhong)類型(xing)的白炭黑,可使硫化(hua)(hua)(hua)膠(jiao)(jiao)的強度增加(jia)(jia)數(shu)十(shi)倍。有(you)時為了降低成(cheng)本或(huo)(huo)改善膠(jiao)(jiao)料性(xing)能及賦予硫化(hua)(hua)(hua)膠(jiao)(jiao)各(ge)種(zhong)(zhong)特殊的性(xing)能,也加(jia)(jia)入相應(ying)的各(ge)種(zhong)(zhong)添加(jia)(jia)劑。硫化(hua)(hua)(hua)劑是各(ge)種(zhong)(zhong)有(you)機過(guo)氧化(hua)(hua)(hua)物(wu)或(huo)(huo)加(jia)(jia)成(cheng)反(fan)應(ying)催化(hua)(hua)(hua)劑。
加工成型方法如圖所示(shi)。一次硫化(hua)(hua)的(de)目(mu)的(de)是進(jin)(jin)行高分(fen)子鏈的(de)交聯(lian)反應;二(er)次硫化(hua)(hua)的(de)目(mu)的(de)是進(jin)(jin)行補充交聯(lian)、驅除硫化(hua)(hua)劑分(fen)解產物(wu)和其他揮發性化(hua)(hua)合物(wu)以穩定(ding)硫化(hua)(hua)膠(jiao)的(de)各(ge)項性能。常(chang)用的(de)設(she)備有(you)開(kai)放式煉膠(jiao)機(ji)、捏合機(ji)及(ji)真空密煉機(ji)。
主要(yao)性能
(1)高溫(wen)(wen)(wen)(wen)性(xing)(xing)(xing)(xing)(xing)(xing)(xing)(xing)能(neng)(neng)(neng)(neng)。硅(gui)橡(xiang)(xiang)膠(jiao)(jiao)顯著的(de)(de)(de)(de)(de)特征是(shi)高溫(wen)(wen)(wen)(wen)穩(wen)定(ding)性(xing)(xing)(xing)(xing)(xing)(xing)(xing)(xing),雖然常(chang)溫(wen)(wen)(wen)(wen)下(xia)(xia)硅(gui)橡(xiang)(xiang)膠(jiao)(jiao)的(de)(de)(de)(de)(de)強(qiang)度僅是(shi)天(tian)然橡(xiang)(xiang)膠(jiao)(jiao)或某些合(he)成橡(xiang)(xiang)膠(jiao)(jiao)的(de)(de)(de)(de)(de)一半,但(dan)在200℃以(yi)上(shang)的(de)(de)(de)(de)(de)高溫(wen)(wen)(wen)(wen)環境下(xia)(xia),硅(gui)橡(xiang)(xiang)膠(jiao)(jiao)仍能(neng)(neng)(neng)(neng)保持一定(ding)的(de)(de)(de)(de)(de)柔韌(ren)性(xing)(xing)(xing)(xing)(xing)(xing)(xing)(xing)、回(hui)彈性(xing)(xing)(xing)(xing)(xing)(xing)(xing)(xing)和表面硬(ying)度,且力學性(xing)(xing)(xing)(xing)(xing)(xing)(xing)(xing)能(neng)(neng)(neng)(neng)無(wu)明(ming)(ming)顯變化(hua)。(2)低溫(wen)(wen)(wen)(wen)性(xing)(xing)(xing)(xing)(xing)(xing)(xing)(xing)能(neng)(neng)(neng)(neng)硅(gui)橡(xiang)(xiang)膠(jiao)(jiao)的(de)(de)(de)(de)(de)玻璃化(hua)溫(wen)(wen)(wen)(wen)度一般(ban)為-70~-50℃,特殊配方可達-100℃,表明(ming)(ming)其(qi)低溫(wen)(wen)(wen)(wen)性(xing)(xing)(xing)(xing)(xing)(xing)(xing)(xing)能(neng)(neng)(neng)(neng)優異。這(zhe)對(dui)航空、宇航工(gong)業的(de)(de)(de)(de)(de)意(yi)義重大。(3)耐(nai)候性(xing)(xing)(xing)(xing)(xing)(xing)(xing)(xing)硅(gui)橡(xiang)(xiang)膠(jiao)(jiao)中Si-O-Si鍵對(dui)氧、臭氧及(ji)紫外線(xian)等(deng)十分穩(wen)定(ding),在不(bu)加任何添加劑的(de)(de)(de)(de)(de)情(qing)況下(xia)(xia),就具有優良(liang)的(de)(de)(de)(de)(de)耐(nai)候性(xing)(xing)(xing)(xing)(xing)(xing)(xing)(xing)。(4)電(dian)氣(qi)性(xing)(xing)(xing)(xing)(xing)(xing)(xing)(xing)能(neng)(neng)(neng)(neng)。硅(gui)橡(xiang)(xiang)膠(jiao)(jiao)具有優異的(de)(de)(de)(de)(de)絕(jue)緣性(xing)(xing)(xing)(xing)(xing)(xing)(xing)(xing)能(neng)(neng)(neng)(neng),耐(nai)電(dian)暈性(xing)(xing)(xing)(xing)(xing)(xing)(xing)(xing)和耐(nai)電(dian)弧性(xing)(xing)(xing)(xing)(xing)(xing)(xing)(xing)也(ye)非(fei)常(chang)好。(5)物(wu)理機(ji)械(xie)性(xing)(xing)(xing)(xing)(xing)(xing)(xing)(xing)能(neng)(neng)(neng)(neng)。硅(gui)橡(xiang)(xiang)膠(jiao)(jiao)常(chang)溫(wen)(wen)(wen)(wen)下(xia)(xia)的(de)(de)(de)(de)(de)物(wu)理機(ji)械(xie)性(xing)(xing)(xing)(xing)(xing)(xing)(xing)(xing)能(neng)(neng)(neng)(neng)比(bi)通用橡(xiang)(xiang)膠(jiao)(jiao)差(cha),但(dan)在150℃的(de)(de)(de)(de)(de)高溫(wen)(wen)(wen)(wen)和-50℃的(de)(de)(de)(de)(de)低溫(wen)(wen)(wen)(wen)下(xia)(xia),其(qi)物(wu)理機(ji)械(xie)性(xing)(xing)(xing)(xing)(xing)(xing)(xing)(xing)能(neng)(neng)(neng)(neng)優于通用橡(xiang)(xiang)膠(jiao)(jiao)。(6)耐(nai)油及(ji)化(hua)學試劑性(xing)(xing)(xing)(xing)(xing)(xing)(xing)(xing)。普通硅(gui)橡(xiang)(xiang)膠(jiao)(jiao)具有中等(deng)的(de)(de)(de)(de)(de)耐(nai)油、耐(nai)溶劑性(xing)(xing)(xing)(xing)(xing)(xing)(xing)(xing)能(neng)(neng)(neng)(neng)。(7)氣(qi)體(ti)透(tou)過性(xing)(xing)(xing)(xing)(xing)(xing)(xing)(xing)能(neng)(neng)(neng)(neng)。室(shi)溫(wen)(wen)(wen)(wen)下(xia)(xia)硅(gui)橡(xiang)(xiang)膠(jiao)(jiao)對(dui)空氣(qi)、氮、氧、二氧化(hua)碳等(deng)氣(qi)體(ti)的(de)(de)(de)(de)(de)透(tou)氣(qi)性(xing)(xing)(xing)(xing)(xing)(xing)(xing)(xing)比(bi)天(tian)然橡(xiang)(xiang)膠(jiao)(jiao)高出30-50倍。(8)生理惰性(xing)(xing)(xing)(xing)(xing)(xing)(xing)(xing)。硅(gui)橡(xiang)(xiang)膠(jiao)(jiao)無(wu)毒(du),無(wu)味,無(wu)嗅,與(yu)人體(ti)組織(zhi)不(bu)粘連,具有抗(kang)凝(ning)血作(zuo)用,對(dui)肌體(ti)組織(zhi)的(de)(de)(de)(de)(de)反應性(xing)(xing)(xing)(xing)(xing)(xing)(xing)(xing)非(fei)常(chang)少。特別適合(he)作(zuo)為醫用材料(liao)。
硅橡膠的用量
據(ju)中(zhong)國汽(qi)(qi)車(che)(che)工(gong)業協會統(tong)計,2012年,汽(qi)(qi)車(che)(che)產銷(xiao)分(fen)別達(da)到1927.18萬(wan)輛(liang)和(he)1930.64萬(wan)輛(liang),同比分(fen)別增長4.63%和(he)4.33%,汽(qi)(qi)車(che)(che)工(gong)業硅橡膠的(de)用(yong)量(liang)(liang)約(yue)達(da)2.0萬(wan)t。根據(ju)觀研(yan)天下的(de)新研(yan)究,增加有(you)(you)機硅材料在汽(qi)(qi)車(che)(che)零部(bu)件方(fang)面的(de)用(yong)量(liang)(liang),可以(yi)大幅度提高(gao)汽(qi)(qi)車(che)(che)的(de)安全性能,因此,汽(qi)(qi)車(che)(che)產量(liang)(liang)和(he)單車(che)(che)用(yong)量(liang)(liang)水平的(de)提高(gao)都將推動(dong)汽(qi)(qi)車(che)(che)工(gong)業對(dui)硅橡膠需求(qiu)的(de)增加。國家鼓勵(li)自主品(pin)(pin)(pin)牌(pai)的(de)汽(qi)(qi)車(che)(che)發展(zhan),關鍵汽(qi)(qi)車(che)(che)零部(bu)件實現自主化,《2012年度黨(dang)政機關公務用(yong)車(che)(che)選用(yong)車(che)(che)型目錄(征求(qiu)意見稿(gao))》為自主品(pin)(pin)(pin)牌(pai)擴大在政府采(cai)購的(de)市場份額,為改變目前國內(nei)政府采(cai)購以(yi)合(he)資品(pin)(pin)(pin)牌(pai)產品(pin)(pin)(pin)為主的(de)局面提供(gong)了保(bao)障。促進自主品(pin)(pin)(pin)牌(pai)發展(zhan),國產汽(qi)(qi)車(che)(che)業的(de)繁榮將為汽(qi)(qi)車(che)(che)膠的(de)應用(yong)提供(gong)有(you)(you)力保(bao)障。預測未(wei)來3年,我(wo)國室溫硫化硅橡膠在汽(qi)(qi)車(che)(che)行業將以(yi)年均20%增長。
此外,硅(gui)橡(xiang)(xiang)膠(jiao)是重要的非石(shi)油基合(he)(he)(he)成(cheng)橡(xiang)(xiang)膠(jiao),約占(zhan)非石(shi)油基合(he)(he)(he)成(cheng)橡(xiang)(xiang)膠(jiao)消(xiao)費(fei)(fei)量的98%。但因(yin)(yin)為(wei)石(shi)油價(jia)格的大(da)幅上漲,同(tong)時(shi)我國(guo)在硅(gui)橡(xiang)(xiang)膠(jiao)的關鍵原料(liao)有機硅(gui)單(dan)(dan)體的生產技(ji)術方(fang)面取得突破,有機硅(gui)單(dan)(dan)體的生產技(ji)術在2005年前(qian)被幾(ji)家跨國(guo)公司壟斷,但目(mu)前(qian)我國(guo)已發展成(cheng)為(wei)全球有機硅(gui)單(dan)(dan)體第1大(da)國(guo),這2個方(fang)面原因(yin)(yin)使硅(gui)橡(xiang)(xiang)膠(jiao)的價(jia)格從2011年起(qi)開始(shi)低于石(shi)油基合(he)(he)(he)成(cheng)橡(xiang)(xiang)膠(jiao),僅(jin)約為(wei)大(da)宗石(shi)油基橡(xiang)(xiang)膠(jiao)的80%~90%,成(cheng)為(wei)廉價(jia)的合(he)(he)(he)成(cheng)橡(xiang)(xiang)膠(jiao),并開始(shi)大(da)規(gui)模替代石(shi)油基合(he)(he)(he)成(cheng)橡(xiang)(xiang)膠(jiao)。這將(jiang)極(ji)大(da)拓展有機硅(gui)產業(ye)的市(shi)場空(kong)間,同(tong)時(shi)將(jiang)帶動硅(gui)油、硅(gui)烷(wan)偶聯劑和硅(gui)樹脂等(deng)其他有機硅(gui)產品的消(xiao)費(fei)(fei)。