橡膠(jiao)是(shi)指(zhi)具有(you)可逆形變(bian)的(de)高彈性聚合(he)物材料，在室(shi)溫下富有(you)彈性，在很(hen)小的(de)外力作用下能(neng)產生較大形變(bian)，除去外力后能(neng)恢復原狀(zhuang)。橡膠(jiao)屬于完全(quan)無定型聚合(he)物，它的(de)玻(bo)璃化轉(zhuan)變(bian)溫度（T g）低，分子量往往很(hen)大，大于幾(ji)十萬。

橡(xiang)膠(jiao)(jiao)分為天然橡(xiang)膠(jiao)(jiao)與合成(cheng)橡(xiang)膠(jiao)(jiao)二種。天然橡(xiang)膠(jiao)(jiao)是(shi)從橡(xiang)膠(jiao)(jiao)樹、橡(xiang)膠(jiao)(jiao)草等(deng)植物中提(ti)取膠(jiao)(jiao)質后(hou)加工制成(cheng)；合成(cheng)橡(xiang)膠(jiao)(jiao)則由各種單體經聚合反應(ying)而(er)得。橡(xiang)膠(jiao)(jiao)制品(pin)廣泛應(ying)用于(yu)工業或(huo)生活(huo)各方面。

通(tong)用(yong)型(xing)橡(xiang)(xiang)(xiang)(xiang)(xiang)膠(jiao)(jiao)(jiao)的(de)綜合(he)(he)性(xing)(xing)(xing)能(neng)(neng)較好，應(ying)用(yong)廣(guang)泛。主(zhu)要有：①天(tian)然(ran)橡(xiang)(xiang)(xiang)(xiang)(xiang)膠(jiao)(jiao)(jiao)，從三葉橡(xiang)(xiang)(xiang)(xiang)(xiang)膠(jiao)(jiao)(jiao)樹的(de)乳膠(jiao)(jiao)(jiao)制(zhi)得(de)(de)，基本化(hua)(hua)學成分為順(shun)(shun)- 聚(ju)異(yi)戊二(er)烯(xi)(xi)。彈性(xing)(xing)(xing)好，強度高，綜合(he)(he)性(xing)(xing)(xing)能(neng)(neng)好。②異(yi)戊橡(xiang)(xiang)(xiang)(xiang)(xiang)膠(jiao)(jiao)(jiao)，全名為順(shun)(shun)-1，4-聚(ju)異(yi)戊二(er)烯(xi)(xi)橡(xiang)(xiang)(xiang)(xiang)(xiang)膠(jiao)(jiao)(jiao)，由異(yi)戊二(er)烯(xi)(xi)制(zhi)得(de)(de)的(de)高順(shun)(shun)式(shi)合(he)(he)成橡(xiang)(xiang)(xiang)(xiang)(xiang)膠(jiao)(jiao)(jiao)，因(yin)其結構和(he)性(xing)(xing)(xing)能(neng)(neng)與天(tian)然(ran)橡(xiang)(xiang)(xiang)(xiang)(xiang)膠(jiao)(jiao)(jiao)近似，故(gu)又稱(cheng)合(he)(he)成天(tian)然(ran)橡(xiang)(xiang)(xiang)(xiang)(xiang)膠(jiao)(jiao)(jiao)。③丁(ding)(ding)苯(ben)橡(xiang)(xiang)(xiang)(xiang)(xiang)膠(jiao)(jiao)(jiao)，簡(jian)稱(cheng)SBR，由丁(ding)(ding)二(er)烯(xi)(xi)和(he)苯(ben)乙烯(xi)(xi)共聚(ju)制(zhi)得(de)(de)。按生(sheng)產方法(fa)分為乳液聚(ju)合(he)(he)丁(ding)(ding)苯(ben)橡(xiang)(xiang)(xiang)(xiang)(xiang)膠(jiao)(jiao)(jiao)和(he)溶液聚(ju)合(he)(he)丁(ding)(ding)苯(ben)橡(xiang)(xiang)(xiang)(xiang)(xiang)膠(jiao)(jiao)(jiao)。其綜合(he)(he)性(xing)(xing)(xing)能(neng)(neng)和(he)化(hua)(hua)學穩定性(xing)(xing)(xing)好。④順(shun)(shun)丁(ding)(ding)橡(xiang)(xiang)(xiang)(xiang)(xiang)膠(jiao)(jiao)(jiao)，全名為順(shun)(shun)式(shi)-1，4-聚(ju)丁(ding)(ding)二(er)烯(xi)(xi)橡(xiang)(xiang)(xiang)(xiang)(xiang)膠(jiao)(jiao)(jiao)，簡(jian)稱(cheng)BR，由丁(ding)(ding)二(er)烯(xi)(xi)聚(ju)合(he)(he)制(zhi)得(de)(de)。與其他通(tong)用(yong)型(xing)橡(xiang)(xiang)(xiang)(xiang)(xiang)膠(jiao)(jiao)(jiao)比，硫化(hua)(hua)后(hou)的(de)順(shun)(shun)丁(ding)(ding)橡(xiang)(xiang)(xiang)(xiang)(xiang)膠(jiao)(jiao)(jiao)的(de)耐寒(han)性(xing)(xing)(xing)、耐磨性(xing)(xing)(xing)和(he)彈性(xing)(xing)(xing)特別(bie)優異(yi)，動負荷下(xia)發熱少，耐老(lao)化(hua)(hua)性(xing)(xing)(xing)能(neng)(neng)好，易與天(tian)然(ran)橡(xiang)(xiang)(xiang)(xiang)(xiang)膠(jiao)(jiao)(jiao)、氯丁(ding)(ding)橡(xiang)(xiang)(xiang)(xiang)(xiang)膠(jiao)(jiao)(jiao)、丁(ding)(ding)腈橡(xiang)(xiang)(xiang)(xiang)(xiang)膠(jiao)(jiao)(jiao)等并用(yong)。⑤氯丁(ding)(ding)橡(xiang)(xiang)(xiang)(xiang)(xiang)膠(jiao)(jiao)(jiao)，簡(jian)稱(cheng)CR，由氯丁(ding)(ding)二(er)烯(xi)(xi)聚(ju)合(he)(he)制(zhi)得(de)(de)。具有良(liang)好的(de)綜合(he)(he)性(xing)(xing)(xing)能(neng)(neng)，耐油、耐燃(ran)、耐氧化(hua)(hua)和(he)耐臭氧。但(dan)其密度較大，常溫下(xia)易結晶變硬，貯存性(xing)(xing)(xing)不好，耐寒(han)性(xing)(xing)(xing)差。