硅橡膠是(shi)指主鏈由(you)硅(gui)(gui)(gui)和氧原(yuan)子(zi)交替構(gou)成(cheng),硅(gui)(gui)(gui)原(yuan)子(zi)上(shang)通(tong)常(chang)連有(you)(you)兩個有(you)(you)機基(ji)(ji)團的(de)(de)(de)橡(xiang)膠(jiao)。普通(tong)的(de)(de)(de)硅(gui)(gui)(gui)橡(xiang)膠(jiao)主要(yao)由(you)含甲基(ji)(ji)和少量(liang)乙烯(xi)基(ji)(ji)的(de)(de)(de)硅(gui)(gui)(gui)氧鏈節組成(cheng)。苯基(ji)(ji)的(de)(de)(de)引(yin)入可提高硅(gui)(gui)(gui)橡(xiang)膠(jiao)的(de)(de)(de)耐高、低溫(wen)性(xing)能,三(san)氟丙基(ji)(ji)及(ji)(ji)氰基(ji)(ji)的(de)(de)(de)引(yin)入則可提高硅(gui)(gui)(gui)橡(xiang)膠(jiao)的(de)(de)(de)耐溫(wen)及(ji)(ji)耐油性(xing)能。硅(gui)(gui)(gui)橡(xiang)膠(jiao)耐低溫(wen)性(xing)能良好,一(yi)般在-55℃下(xia)仍能工作。引(yin)入苯基(ji)(ji)后,可達-73℃。硅(gui)(gui)(gui)橡(xiang)膠(jiao)的(de)(de)(de)耐熱性(xing)能也很突(tu)(tu)出,在180℃下(xia)可長(chang)期(qi)工作,稍(shao)高于200℃也能承受(shou)數(shu)周或更長(chang)時間(jian)仍有(you)(you)彈性(xing),瞬(shun)時可耐300℃以(yi)上(shang)的(de)(de)(de)高溫(wen)。硅(gui)(gui)(gui)橡(xiang)膠(jiao)的(de)(de)(de)透氣性(xing)好,氧氣透過率在合成(cheng)聚合物(wu)中(zhong)是(shi)較高的(de)(de)(de)。此外,硅(gui)(gui)(gui)橡(xiang)膠(jiao)還具有(you)(you)生理惰性(xing)、不(bu)會導致凝血的(de)(de)(de)突(tu)(tu)出特性(xing),因此在醫(yi)用領域應用廣泛(fan)。
主要品種
硅橡(xiang)膠(jiao)(jiao)分類的方法很(hen)多,通(tong)常按固化前的形態分為固體(ti)硅橡(xiang)膠(jiao)(jiao)和液體(ti)硅橡(xiang)膠(jiao)(jiao);按硫(liu)化溫(wen)度(du)分為室溫(wen)硫(liu)化硅橡(xiang)膠(jiao)(jiao),高(gao)溫(wen)硫(liu)化硅橡(xiang)膠(jiao)(jiao);按所用(yong)(yong)單體(ti)的不(bu)(bu)同(tong),可(ke)分為甲基(ji)(ji)乙烯基(ji)(ji)硅橡(xiang)膠(jiao)(jiao),甲基(ji)(ji)苯(ben)基(ji)(ji)乙烯基(ji)(ji)硅橡(xiang)膠(jiao)(jiao)、氟硅,腈硅橡(xiang)膠(jiao)(jiao)等;按性能和用(yong)(yong)途的不(bu)(bu)同(tong)又可(ke)分為通(tong)用(yong)(yong)型(xing)、超(chao)耐低(di)溫(wen)型(xing)、超(chao)耐高(gao)溫(wen)型(xing)、高(gao)強(qiang)力型(xing)、耐油型(xing)、醫用(yong)(yong)型(xing)等等。
發展史
硅橡(xiang)(xiang)膠(jiao)早(zao)期是由美國(guo)(guo)(guo)以三氯化(hua)鐵為催(cui)化(hua)劑(ji)合成的(de)。1945年(nian),硅橡(xiang)(xiang)膠(jiao)產(chan)(chan)品問世。1948年(nian),采(cai)用高比表面積的(de)氣相(xiang)法白炭黑補(bu)強的(de)硅橡(xiang)(xiang)膠(jiao)研制(zhi)成功,使硅橡(xiang)(xiang)膠(jiao)的(de)性能躍升到實用階段,奠定了現代硅橡(xiang)(xiang)膠(jiao)生(sheng)產(chan)(chan)技術的(de)基礎。從二甲基二氯硅烷合成開(kai)始生(sheng)產(chan)(chan)硅橡(xiang)(xiang)膠(jiao)的(de)國(guo)(guo)(guo)家(jia)有(you)美國(guo)(guo)(guo)。俄羅斯、德(de)國(guo)(guo)(guo)、日本、韓國(guo)(guo)(guo)和中(zhong)(zhong)國(guo)(guo)(guo)等(deng)。中(zhong)(zhong)國(guo)(guo)(guo)硅橡(xiang)(xiang)膠(jiao)的(de)工(gong)業化(hua)研究始于(yu)1957年(nian),多家(jia)研究所和企業陸續開(kai)發出各種硅橡(xiang)(xiang)膠(jiao)。到2003年(nian)底(di),中(zhong)(zhong)國(guo)(guo)(guo)硅橡(xiang)(xiang)膠(jiao)生(sheng)產(chan)(chan)能力為135千噸(dun),其中(zhong)(zhong)高溫膠(jiao)100千噸(dun)。
高溫硫化硅橡膠
高溫硫(liu)化(hua)(hua)硅(gui)橡(xiang)膠(jiao)(jiao)是(shi)指聚(ju)硅(gui)氧烷(wan)變成(cheng)彈性(xing)體的(de)(de)過(guo)程(cheng)是(shi)經過(guo)高溫(110-170℃)硫(liu)化(hua)(hua)成(cheng)型的(de)(de)。它主要以高分子量的(de)(de)聚(ju)甲基乙烯基硅(gui)氧烷(wan)為生膠(jiao)(jiao),混入補強填料、硫(liu)化(hua)(hua)劑(ji)等,在加(jia)熱加(jia)壓(ya)下硫(liu)化(hua)(hua)成(cheng)彈性(xing)體。硅(gui)橡(xiang)膠(jiao)(jiao)的(de)(de)補強主要是(shi)各種類(lei)型的(de)(de)白炭黑,可使硫(liu)化(hua)(hua)膠(jiao)(jiao)的(de)(de)強度增加(jia)數十倍。有時為了降低成(cheng)本或(huo)改善(shan)膠(jiao)(jiao)料性(xing)能及賦予硫(liu)化(hua)(hua)膠(jiao)(jiao)各種特殊(shu)的(de)(de)性(xing)能,也加(jia)入相應的(de)(de)各種添(tian)加(jia)劑(ji)。硫(liu)化(hua)(hua)劑(ji)是(shi)各種有機過(guo)氧化(hua)(hua)物或(huo)加(jia)成(cheng)反應催化(hua)(hua)劑(ji)。
加(jia)工成型方法如(ru)圖所示。一(yi)次硫(liu)化的(de)目的(de)是進行(xing)高分子(zi)鏈的(de)交聯反應;二次硫(liu)化的(de)目的(de)是進行(xing)補充交聯、驅除(chu)硫(liu)化劑(ji)分解(jie)產物和其(qi)他(ta)揮發(fa)性化合(he)物以穩定硫(liu)化膠的(de)各項性能。常(chang)用的(de)設備(bei)有開放(fang)式煉膠機、捏(nie)合(he)機及真空密煉機。
主要性能
(1)高溫(wen)(wen)(wen)性(xing)(xing)(xing)(xing)(xing)(xing)能。硅(gui)(gui)(gui)(gui)橡(xiang)(xiang)(xiang)(xiang)膠(jiao)顯著的(de)(de)特(te)征是高溫(wen)(wen)(wen)穩(wen)定(ding)(ding)(ding)性(xing)(xing)(xing)(xing)(xing)(xing),雖然(ran)常(chang)溫(wen)(wen)(wen)下(xia)硅(gui)(gui)(gui)(gui)橡(xiang)(xiang)(xiang)(xiang)膠(jiao)的(de)(de)強度(du)僅是天然(ran)橡(xiang)(xiang)(xiang)(xiang)膠(jiao)或某些(xie)合成橡(xiang)(xiang)(xiang)(xiang)膠(jiao)的(de)(de)一半,但在(zai)200℃以上的(de)(de)高溫(wen)(wen)(wen)環境下(xia),硅(gui)(gui)(gui)(gui)橡(xiang)(xiang)(xiang)(xiang)膠(jiao)仍能保持(chi)一定(ding)(ding)(ding)的(de)(de)柔韌性(xing)(xing)(xing)(xing)(xing)(xing)、回彈性(xing)(xing)(xing)(xing)(xing)(xing)和(he)表面硬度(du),且力學性(xing)(xing)(xing)(xing)(xing)(xing)能無明顯變(bian)化(hua)。(2)低溫(wen)(wen)(wen)性(xing)(xing)(xing)(xing)(xing)(xing)能硅(gui)(gui)(gui)(gui)橡(xiang)(xiang)(xiang)(xiang)膠(jiao)的(de)(de)玻璃化(hua)溫(wen)(wen)(wen)度(du)一般為-70~-50℃,特(te)殊(shu)配方可達-100℃,表明其(qi)低溫(wen)(wen)(wen)性(xing)(xing)(xing)(xing)(xing)(xing)能優(you)異(yi)。這對(dui)航空、宇(yu)航工業的(de)(de)意義重大。(3)耐(nai)(nai)候(hou)性(xing)(xing)(xing)(xing)(xing)(xing)硅(gui)(gui)(gui)(gui)橡(xiang)(xiang)(xiang)(xiang)膠(jiao)中(zhong)Si-O-Si鍵(jian)對(dui)氧(yang)、臭(chou)氧(yang)及(ji)紫外線等(deng)十分穩(wen)定(ding)(ding)(ding),在(zai)不加(jia)任何添加(jia)劑(ji)的(de)(de)情(qing)況下(xia),就具有優(you)良的(de)(de)耐(nai)(nai)候(hou)性(xing)(xing)(xing)(xing)(xing)(xing)。(4)電(dian)(dian)氣(qi)(qi)(qi)性(xing)(xing)(xing)(xing)(xing)(xing)能。硅(gui)(gui)(gui)(gui)橡(xiang)(xiang)(xiang)(xiang)膠(jiao)具有優(you)異(yi)的(de)(de)絕緣性(xing)(xing)(xing)(xing)(xing)(xing)能,耐(nai)(nai)電(dian)(dian)暈性(xing)(xing)(xing)(xing)(xing)(xing)和(he)耐(nai)(nai)電(dian)(dian)弧性(xing)(xing)(xing)(xing)(xing)(xing)也非常(chang)好。(5)物(wu)理(li)機(ji)械性(xing)(xing)(xing)(xing)(xing)(xing)能。硅(gui)(gui)(gui)(gui)橡(xiang)(xiang)(xiang)(xiang)膠(jiao)常(chang)溫(wen)(wen)(wen)下(xia)的(de)(de)物(wu)理(li)機(ji)械性(xing)(xing)(xing)(xing)(xing)(xing)能比通用橡(xiang)(xiang)(xiang)(xiang)膠(jiao)差(cha),但在(zai)150℃的(de)(de)高溫(wen)(wen)(wen)和(he)-50℃的(de)(de)低溫(wen)(wen)(wen)下(xia),其(qi)物(wu)理(li)機(ji)械性(xing)(xing)(xing)(xing)(xing)(xing)能優(you)于(yu)通用橡(xiang)(xiang)(xiang)(xiang)膠(jiao)。(6)耐(nai)(nai)油及(ji)化(hua)學試劑(ji)性(xing)(xing)(xing)(xing)(xing)(xing)。普(pu)通硅(gui)(gui)(gui)(gui)橡(xiang)(xiang)(xiang)(xiang)膠(jiao)具有中(zhong)等(deng)的(de)(de)耐(nai)(nai)油、耐(nai)(nai)溶劑(ji)性(xing)(xing)(xing)(xing)(xing)(xing)能。(7)氣(qi)(qi)(qi)體(ti)(ti)(ti)透(tou)過性(xing)(xing)(xing)(xing)(xing)(xing)能。室溫(wen)(wen)(wen)下(xia)硅(gui)(gui)(gui)(gui)橡(xiang)(xiang)(xiang)(xiang)膠(jiao)對(dui)空氣(qi)(qi)(qi)、氮、氧(yang)、二(er)氧(yang)化(hua)碳等(deng)氣(qi)(qi)(qi)體(ti)(ti)(ti)的(de)(de)透(tou)氣(qi)(qi)(qi)性(xing)(xing)(xing)(xing)(xing)(xing)比天然(ran)橡(xiang)(xiang)(xiang)(xiang)膠(jiao)高出30-50倍(bei)。(8)生理(li)惰性(xing)(xing)(xing)(xing)(xing)(xing)。硅(gui)(gui)(gui)(gui)橡(xiang)(xiang)(xiang)(xiang)膠(jiao)無毒,無味(wei),無嗅,與人(ren)體(ti)(ti)(ti)組(zu)織不粘連,具有抗凝(ning)血作(zuo)用,對(dui)肌體(ti)(ti)(ti)組(zu)織的(de)(de)反應性(xing)(xing)(xing)(xing)(xing)(xing)非常(chang)少。特(te)別適合作(zuo)為醫用材料。
硅橡膠的用量
據中國(guo)汽(qi)(qi)(qi)(qi)車工(gong)業協(xie)會(hui)統(tong)計,2012年(nian),汽(qi)(qi)(qi)(qi)車產(chan)銷分別(bie)達到1927.18萬(wan)(wan)輛和(he)1930.64萬(wan)(wan)輛,同比分別(bie)增長4.63%和(he)4.33%,汽(qi)(qi)(qi)(qi)車工(gong)業硅(gui)橡膠的(de)(de)(de)(de)用(yong)(yong)(yong)量(liang)(liang)約達2.0萬(wan)(wan)t。根據觀研(yan)天下的(de)(de)(de)(de)新(xin)研(yan)究,增加(jia)有機(ji)(ji)硅(gui)材料在汽(qi)(qi)(qi)(qi)車零部(bu)件方(fang)面(mian)(mian)的(de)(de)(de)(de)用(yong)(yong)(yong)量(liang)(liang),可以(yi)(yi)大幅度提高(gao)汽(qi)(qi)(qi)(qi)車的(de)(de)(de)(de)安全性(xing)能,因此(ci),汽(qi)(qi)(qi)(qi)車產(chan)量(liang)(liang)和(he)單車用(yong)(yong)(yong)量(liang)(liang)水(shui)平的(de)(de)(de)(de)提高(gao)都(dou)將推(tui)動(dong)汽(qi)(qi)(qi)(qi)車工(gong)業對硅(gui)橡膠需求的(de)(de)(de)(de)增加(jia)。國(guo)家鼓勵自(zi)主(zhu)(zhu)品牌(pai)的(de)(de)(de)(de)汽(qi)(qi)(qi)(qi)車發(fa)展,關鍵汽(qi)(qi)(qi)(qi)車零部(bu)件實現自(zi)主(zhu)(zhu)化,《2012年(nian)度黨政(zheng)機(ji)(ji)關公務用(yong)(yong)(yong)車選用(yong)(yong)(yong)車型目(mu)錄(征求意見稿)》為自(zi)主(zhu)(zhu)品牌(pai)擴大在政(zheng)府采購的(de)(de)(de)(de)市場份額,為改變目(mu)前國(guo)內政(zheng)府采購以(yi)(yi)合資品牌(pai)產(chan)品為主(zhu)(zhu)的(de)(de)(de)(de)局面(mian)(mian)提供了(le)保(bao)障。促進自(zi)主(zhu)(zhu)品牌(pai)發(fa)展,國(guo)產(chan)汽(qi)(qi)(qi)(qi)車業的(de)(de)(de)(de)繁榮將為汽(qi)(qi)(qi)(qi)車膠的(de)(de)(de)(de)應用(yong)(yong)(yong)提供有力保(bao)障。預測(ce)未來3年(nian),我(wo)國(guo)室(shi)溫硫(liu)化硅(gui)橡膠在汽(qi)(qi)(qi)(qi)車行業將以(yi)(yi)年(nian)均20%增長。
此外,硅(gui)(gui)橡(xiang)(xiang)(xiang)膠(jiao)(jiao)是重要的非(fei)石油(you)基合(he)成(cheng)(cheng)橡(xiang)(xiang)(xiang)膠(jiao)(jiao),約(yue)占非(fei)石油(you)基合(he)成(cheng)(cheng)橡(xiang)(xiang)(xiang)膠(jiao)(jiao)消費(fei)量的98%。但(dan)因為(wei)(wei)石油(you)價(jia)格的大(da)(da)(da)幅上(shang)漲(zhang),同時我國(guo)在(zai)硅(gui)(gui)橡(xiang)(xiang)(xiang)膠(jiao)(jiao)的關鍵(jian)原料有(you)機(ji)硅(gui)(gui)單體的生產(chan)技術方面取得突破,有(you)機(ji)硅(gui)(gui)單體的生產(chan)技術在(zai)2005年前被幾家(jia)跨國(guo)公司壟斷,但(dan)目前我國(guo)已發(fa)展成(cheng)(cheng)為(wei)(wei)全球有(you)機(ji)硅(gui)(gui)單體第1大(da)(da)(da)國(guo),這2個方面原因使硅(gui)(gui)橡(xiang)(xiang)(xiang)膠(jiao)(jiao)的價(jia)格從(cong)2011年起開始低(di)于(yu)石油(you)基合(he)成(cheng)(cheng)橡(xiang)(xiang)(xiang)膠(jiao)(jiao),僅約(yue)為(wei)(wei)大(da)(da)(da)宗(zong)石油(you)基橡(xiang)(xiang)(xiang)膠(jiao)(jiao)的80%~90%,成(cheng)(cheng)為(wei)(wei)廉價(jia)的合(he)成(cheng)(cheng)橡(xiang)(xiang)(xiang)膠(jiao)(jiao),并開始大(da)(da)(da)規模替代石油(you)基合(he)成(cheng)(cheng)橡(xiang)(xiang)(xiang)膠(jiao)(jiao)。這將極大(da)(da)(da)拓展有(you)機(ji)硅(gui)(gui)產(chan)業的市場空間,同時將帶(dai)動硅(gui)(gui)油(you)、硅(gui)(gui)烷偶聯劑和硅(gui)(gui)樹脂(zhi)等其他有(you)機(ji)硅(gui)(gui)產(chan)品的消費(fei)。