硅橡膠是指主(zhu)鏈由硅(gui)和氧(yang)原(yuan)(yuan)子交替(ti)構成,硅(gui)原(yuan)(yuan)子上(shang)通常連有(you)兩(liang)個有(you)機基團的橡(xiang)(xiang)(xiang)膠(jiao)。普通的硅(gui)橡(xiang)(xiang)(xiang)膠(jiao)主(zhu)要由含(han)甲(jia)基和少(shao)量乙烯基的硅(gui)氧(yang)鏈節組成。苯基的引入可(ke)提高硅(gui)橡(xiang)(xiang)(xiang)膠(jiao)的耐(nai)(nai)高、低溫性(xing)(xing)(xing)(xing)能(neng),三氟丙基及氰基的引入則可(ke)提高硅(gui)橡(xiang)(xiang)(xiang)膠(jiao)的耐(nai)(nai)溫及耐(nai)(nai)油性(xing)(xing)(xing)(xing)能(neng)。硅(gui)橡(xiang)(xiang)(xiang)膠(jiao)耐(nai)(nai)低溫性(xing)(xing)(xing)(xing)能(neng)良好,一般在(zai)(zai)-55℃下仍能(neng)工(gong)作。引入苯基后,可(ke)達-73℃。硅(gui)橡(xiang)(xiang)(xiang)膠(jiao)的耐(nai)(nai)熱性(xing)(xing)(xing)(xing)能(neng)也很突出,在(zai)(zai)180℃下可(ke)長期工(gong)作,稍高于200℃也能(neng)承(cheng)受數(shu)周或更長時間仍有(you)彈性(xing)(xing)(xing)(xing),瞬(shun)時可(ke)耐(nai)(nai)300℃以上(shang)的高溫。硅(gui)橡(xiang)(xiang)(xiang)膠(jiao)的透氣(qi)性(xing)(xing)(xing)(xing)好,氧(yang)氣(qi)透過率在(zai)(zai)合成聚合物(wu)中是較高的。此(ci)外,硅(gui)橡(xiang)(xiang)(xiang)膠(jiao)還具有(you)生理(li)惰(duo)性(xing)(xing)(xing)(xing)、不會(hui)導致(zhi)凝血的突出特性(xing)(xing)(xing)(xing),因(yin)此(ci)在(zai)(zai)醫用(yong)領域應用(yong)廣泛。
主要品種
硅(gui)(gui)(gui)橡(xiang)膠(jiao)分(fen)類(lei)的方法很多,通(tong)常按固化(hua)前的形(xing)態分(fen)為固體(ti)硅(gui)(gui)(gui)橡(xiang)膠(jiao)和(he)液(ye)體(ti)硅(gui)(gui)(gui)橡(xiang)膠(jiao);按硫(liu)化(hua)溫(wen)(wen)(wen)度(du)分(fen)為室溫(wen)(wen)(wen)硫(liu)化(hua)硅(gui)(gui)(gui)橡(xiang)膠(jiao),高(gao)溫(wen)(wen)(wen)硫(liu)化(hua)硅(gui)(gui)(gui)橡(xiang)膠(jiao);按所用(yong)單體(ti)的不(bu)同(tong),可(ke)分(fen)為甲基(ji)乙(yi)烯基(ji)硅(gui)(gui)(gui)橡(xiang)膠(jiao),甲基(ji)苯基(ji)乙(yi)烯基(ji)硅(gui)(gui)(gui)橡(xiang)膠(jiao)、氟硅(gui)(gui)(gui),腈硅(gui)(gui)(gui)橡(xiang)膠(jiao)等(deng);按性能和(he)用(yong)途的不(bu)同(tong)又可(ke)分(fen)為通(tong)用(yong)型(xing)、超耐(nai)低(di)溫(wen)(wen)(wen)型(xing)、超耐(nai)高(gao)溫(wen)(wen)(wen)型(xing)、高(gao)強力(li)型(xing)、耐(nai)油型(xing)、醫用(yong)型(xing)等(deng)等(deng)。
發展史
硅(gui)(gui)(gui)(gui)橡(xiang)膠早期是由(you)美國以三氯化鐵為催化劑合(he)成的(de)。1945年(nian),硅(gui)(gui)(gui)(gui)橡(xiang)膠產(chan)(chan)品問(wen)世。1948年(nian),采用高(gao)比表面(mian)積的(de)氣(qi)相法白(bai)炭黑補(bu)強的(de)硅(gui)(gui)(gui)(gui)橡(xiang)膠研制成功,使硅(gui)(gui)(gui)(gui)橡(xiang)膠的(de)性(xing)能(neng)躍升到實用階段,奠定(ding)了現代硅(gui)(gui)(gui)(gui)橡(xiang)膠生產(chan)(chan)技(ji)術的(de)基(ji)礎。從二甲(jia)基(ji)二氯硅(gui)(gui)(gui)(gui)烷(wan)合(he)成開始生產(chan)(chan)硅(gui)(gui)(gui)(gui)橡(xiang)膠的(de)國家(jia)有美國。俄羅斯、德國、日(ri)本、韓國和(he)中國等(deng)。中國硅(gui)(gui)(gui)(gui)橡(xiang)膠的(de)工(gong)業化研究始于1957年(nian),多家(jia)研究所和(he)企業陸(lu)續(xu)開發(fa)出各種硅(gui)(gui)(gui)(gui)橡(xiang)膠。到2003年(nian)底,中國硅(gui)(gui)(gui)(gui)橡(xiang)膠生產(chan)(chan)能(neng)力(li)為135千噸(dun),其中高(gao)溫膠100千噸(dun)。
高溫硫化硅橡膠
高溫(wen)硫化(hua)(hua)(hua)(hua)硅(gui)橡膠(jiao)(jiao)是(shi)指(zhi)聚硅(gui)氧(yang)烷(wan)變成(cheng)彈(dan)性(xing)體的過(guo)(guo)程是(shi)經過(guo)(guo)高溫(wen)(110-170℃)硫化(hua)(hua)(hua)(hua)成(cheng)型的。它主要(yao)以高分子量的聚甲基乙烯基硅(gui)氧(yang)烷(wan)為生膠(jiao)(jiao),混入補強填料、硫化(hua)(hua)(hua)(hua)劑等,在加(jia)熱加(jia)壓下硫化(hua)(hua)(hua)(hua)成(cheng)彈(dan)性(xing)體。硅(gui)橡膠(jiao)(jiao)的補強主要(yao)是(shi)各(ge)種類型的白炭黑,可(ke)使硫化(hua)(hua)(hua)(hua)膠(jiao)(jiao)的強度(du)增加(jia)數十(shi)倍。有時為了降低成(cheng)本(ben)或改(gai)善膠(jiao)(jiao)料性(xing)能及賦予硫化(hua)(hua)(hua)(hua)膠(jiao)(jiao)各(ge)種特殊(shu)的性(xing)能,也加(jia)入相(xiang)應(ying)的各(ge)種添(tian)加(jia)劑。硫化(hua)(hua)(hua)(hua)劑是(shi)各(ge)種有機過(guo)(guo)氧(yang)化(hua)(hua)(hua)(hua)物(wu)或加(jia)成(cheng)反應(ying)催化(hua)(hua)(hua)(hua)劑。
加工成型方法如圖所示(shi)。一次硫化的目的是進行高分(fen)子鏈的交聯反應;二次硫化的目的是進行補充交聯、驅除硫化劑分(fen)解產物(wu)和(he)其他揮(hui)發(fa)性(xing)(xing)化合(he)物(wu)以(yi)穩定(ding)硫化膠的各(ge)項(xiang)性(xing)(xing)能(neng)。常用(yong)的設備(bei)有開放式煉膠機(ji)、捏合(he)機(ji)及真空密(mi)煉機(ji)。
主要性能
(1)高溫(wen)(wen)(wen)(wen)性(xing)(xing)(xing)(xing)能(neng)(neng)(neng)(neng)。硅橡(xiang)(xiang)膠(jiao)(jiao)(jiao)顯著的(de)(de)(de)特征是高溫(wen)(wen)(wen)(wen)穩定性(xing)(xing)(xing)(xing),雖然常溫(wen)(wen)(wen)(wen)下(xia)硅橡(xiang)(xiang)膠(jiao)(jiao)(jiao)的(de)(de)(de)強(qiang)度僅是天然橡(xiang)(xiang)膠(jiao)(jiao)(jiao)或某(mou)些合成橡(xiang)(xiang)膠(jiao)(jiao)(jiao)的(de)(de)(de)一(yi)(yi)半,但在200℃以上的(de)(de)(de)高溫(wen)(wen)(wen)(wen)環(huan)境下(xia),硅橡(xiang)(xiang)膠(jiao)(jiao)(jiao)仍能(neng)(neng)(neng)(neng)保持一(yi)(yi)定的(de)(de)(de)柔韌性(xing)(xing)(xing)(xing)、回彈性(xing)(xing)(xing)(xing)和表(biao)面(mian)硬度,且力學性(xing)(xing)(xing)(xing)能(neng)(neng)(neng)(neng)無明(ming)顯變化。(2)低溫(wen)(wen)(wen)(wen)性(xing)(xing)(xing)(xing)能(neng)(neng)(neng)(neng)硅橡(xiang)(xiang)膠(jiao)(jiao)(jiao)的(de)(de)(de)玻璃(li)化溫(wen)(wen)(wen)(wen)度一(yi)(yi)般為(wei)-70~-50℃,特殊(shu)配方可達-100℃,表(biao)明(ming)其低溫(wen)(wen)(wen)(wen)性(xing)(xing)(xing)(xing)能(neng)(neng)(neng)(neng)優(you)異。這對(dui)航空、宇航工業的(de)(de)(de)意義(yi)重大。(3)耐(nai)(nai)候性(xing)(xing)(xing)(xing)硅橡(xiang)(xiang)膠(jiao)(jiao)(jiao)中(zhong)Si-O-Si鍵對(dui)氧(yang)(yang)(yang)、臭(chou)氧(yang)(yang)(yang)及紫外線等十分穩定,在不(bu)加(jia)任(ren)何添加(jia)劑(ji)的(de)(de)(de)情況下(xia),就具(ju)(ju)有(you)(you)優(you)良的(de)(de)(de)耐(nai)(nai)候性(xing)(xing)(xing)(xing)。(4)電氣性(xing)(xing)(xing)(xing)能(neng)(neng)(neng)(neng)。硅橡(xiang)(xiang)膠(jiao)(jiao)(jiao)具(ju)(ju)有(you)(you)優(you)異的(de)(de)(de)絕緣性(xing)(xing)(xing)(xing)能(neng)(neng)(neng)(neng),耐(nai)(nai)電暈性(xing)(xing)(xing)(xing)和耐(nai)(nai)電弧(hu)性(xing)(xing)(xing)(xing)也非(fei)常好(hao)。(5)物理機械(xie)性(xing)(xing)(xing)(xing)能(neng)(neng)(neng)(neng)。硅橡(xiang)(xiang)膠(jiao)(jiao)(jiao)常溫(wen)(wen)(wen)(wen)下(xia)的(de)(de)(de)物理機械(xie)性(xing)(xing)(xing)(xing)能(neng)(neng)(neng)(neng)比(bi)通(tong)(tong)用橡(xiang)(xiang)膠(jiao)(jiao)(jiao)差,但在150℃的(de)(de)(de)高溫(wen)(wen)(wen)(wen)和-50℃的(de)(de)(de)低溫(wen)(wen)(wen)(wen)下(xia),其物理機械(xie)性(xing)(xing)(xing)(xing)能(neng)(neng)(neng)(neng)優(you)于(yu)通(tong)(tong)用橡(xiang)(xiang)膠(jiao)(jiao)(jiao)。(6)耐(nai)(nai)油及化學試劑(ji)性(xing)(xing)(xing)(xing)。普通(tong)(tong)硅橡(xiang)(xiang)膠(jiao)(jiao)(jiao)具(ju)(ju)有(you)(you)中(zhong)等的(de)(de)(de)耐(nai)(nai)油、耐(nai)(nai)溶劑(ji)性(xing)(xing)(xing)(xing)能(neng)(neng)(neng)(neng)。(7)氣體透過性(xing)(xing)(xing)(xing)能(neng)(neng)(neng)(neng)。室溫(wen)(wen)(wen)(wen)下(xia)硅橡(xiang)(xiang)膠(jiao)(jiao)(jiao)對(dui)空氣、氮(dan)、氧(yang)(yang)(yang)、二氧(yang)(yang)(yang)化碳等氣體的(de)(de)(de)透氣性(xing)(xing)(xing)(xing)比(bi)天然橡(xiang)(xiang)膠(jiao)(jiao)(jiao)高出30-50倍。(8)生理惰性(xing)(xing)(xing)(xing)。硅橡(xiang)(xiang)膠(jiao)(jiao)(jiao)無毒(du),無味(wei),無嗅,與人體組織(zhi)不(bu)粘連,具(ju)(ju)有(you)(you)抗凝血作用,對(dui)肌體組織(zhi)的(de)(de)(de)反(fan)應性(xing)(xing)(xing)(xing)非(fei)常少。特別適合作為(wei)醫用材料。
硅橡膠的用量
據中國(guo)汽(qi)(qi)(qi)(qi)車(che)工(gong)業(ye)(ye)協(xie)會(hui)統計,2012年(nian)(nian),汽(qi)(qi)(qi)(qi)車(che)產銷分別達(da)(da)到(dao)1927.18萬(wan)輛(liang)和1930.64萬(wan)輛(liang),同比(bi)分別增(zeng)長4.63%和4.33%,汽(qi)(qi)(qi)(qi)車(che)工(gong)業(ye)(ye)硅(gui)橡膠(jiao)(jiao)的(de)(de)用(yong)量(liang)約達(da)(da)2.0萬(wan)t。根據觀(guan)研天下的(de)(de)新研究,增(zeng)加(jia)有(you)機硅(gui)材料在汽(qi)(qi)(qi)(qi)車(che)零(ling)部(bu)件(jian)方面的(de)(de)用(yong)量(liang),可以(yi)大(da)幅度(du)提高(gao)汽(qi)(qi)(qi)(qi)車(che)的(de)(de)安全性能,因此,汽(qi)(qi)(qi)(qi)車(che)產量(liang)和單車(che)用(yong)量(liang)水平的(de)(de)提高(gao)都(dou)將推(tui)動汽(qi)(qi)(qi)(qi)車(che)工(gong)業(ye)(ye)對硅(gui)橡膠(jiao)(jiao)需(xu)求的(de)(de)增(zeng)加(jia)。國(guo)家鼓(gu)勵自主(zhu)品牌(pai)的(de)(de)汽(qi)(qi)(qi)(qi)車(che)發展(zhan),關(guan)鍵汽(qi)(qi)(qi)(qi)車(che)零(ling)部(bu)件(jian)實現自主(zhu)化,《2012年(nian)(nian)度(du)黨政(zheng)機關(guan)公務用(yong)車(che)選用(yong)車(che)型(xing)目(mu)錄(征求意(yi)見(jian)稿)》為自主(zhu)品牌(pai)擴大(da)在政(zheng)府(fu)采購的(de)(de)市(shi)場份額,為改變目(mu)前國(guo)內(nei)政(zheng)府(fu)采購以(yi)合資品牌(pai)產品為主(zhu)的(de)(de)局面提供了保障。促進自主(zhu)品牌(pai)發展(zhan),國(guo)產汽(qi)(qi)(qi)(qi)車(che)業(ye)(ye)的(de)(de)繁榮將為汽(qi)(qi)(qi)(qi)車(che)膠(jiao)(jiao)的(de)(de)應(ying)用(yong)提供有(you)力保障。預測未(wei)來3年(nian)(nian),我國(guo)室溫硫化硅(gui)橡膠(jiao)(jiao)在汽(qi)(qi)(qi)(qi)車(che)行(xing)業(ye)(ye)將以(yi)年(nian)(nian)均20%增(zeng)長。
此(ci)外,硅(gui)(gui)橡(xiang)(xiang)膠是(shi)重要(yao)的(de)(de)非(fei)石油(you)基合(he)成(cheng)(cheng)橡(xiang)(xiang)膠,約(yue)占非(fei)石油(you)基合(he)成(cheng)(cheng)橡(xiang)(xiang)膠消(xiao)費(fei)量的(de)(de)98%。但(dan)因(yin)為石油(you)價格的(de)(de)大(da)(da)幅上漲,同時我(wo)(wo)國(guo)(guo)在(zai)(zai)硅(gui)(gui)橡(xiang)(xiang)膠的(de)(de)關鍵原(yuan)料有(you)機(ji)(ji)硅(gui)(gui)單(dan)體(ti)的(de)(de)生產(chan)技(ji)術方面取得突(tu)破,有(you)機(ji)(ji)硅(gui)(gui)單(dan)體(ti)的(de)(de)生產(chan)技(ji)術在(zai)(zai)2005年前被幾家跨國(guo)(guo)公(gong)司壟(long)斷(duan),但(dan)目(mu)前我(wo)(wo)國(guo)(guo)已發展成(cheng)(cheng)為全(quan)球有(you)機(ji)(ji)硅(gui)(gui)單(dan)體(ti)第1大(da)(da)國(guo)(guo),這(zhe)2個方面原(yuan)因(yin)使硅(gui)(gui)橡(xiang)(xiang)膠的(de)(de)價格從2011年起開(kai)始低于石油(you)基合(he)成(cheng)(cheng)橡(xiang)(xiang)膠,僅約(yue)為大(da)(da)宗石油(you)基橡(xiang)(xiang)膠的(de)(de)80%~90%,成(cheng)(cheng)為廉(lian)價的(de)(de)合(he)成(cheng)(cheng)橡(xiang)(xiang)膠,并開(kai)始大(da)(da)規(gui)模替代石油(you)基合(he)成(cheng)(cheng)橡(xiang)(xiang)膠。這(zhe)將極大(da)(da)拓展有(you)機(ji)(ji)硅(gui)(gui)產(chan)業(ye)的(de)(de)市場空間,同時將帶動硅(gui)(gui)油(you)、硅(gui)(gui)烷偶(ou)聯劑和(he)硅(gui)(gui)樹脂(zhi)等其他有(you)機(ji)(ji)硅(gui)(gui)產(chan)品(pin)的(de)(de)消(xiao)費(fei)。