(2)光气直接法
光气属于酰氯,活性高,可以与羟基化合物直接酯化。光气法合成聚碳酸酯多采用界面缩聚技术。双酚A和氢氧化钠配成双酚钠水溶液作为水相,光气的有机溶液(如二氯甲烷)为另一相,以胺类(如四丁基溴化铵)作催化剂,在50℃下反应。反应主要在水相一侧,反应器内的搅拌要保证有机相中的光气及时地扩散至界面,以供反应。光气直接法比酯交换法经济,所得分子量也较高。
界面缩聚是不可逆反应,并不严格要求两基团数相等,一般光气稍过量,以弥补水解损失。可加少量单官能团苯酚进行端基封锁,控制分子量。聚碳酸酯用双酚A的纯度要求高,有特定的规格,不宜含有单酚和三酚,否则,得不到高分子量的聚碳酸酯,或产生交联。
折叠加工
PC可注塑、挤出、模压、吹塑、热成型、印刷、粘接、涂覆和机加工,Zui重要的加工方法是注塑。成型之前必须预干燥,水分含量应低于0.02%,微量水份在高温下加工会使制品产生白浊色泽,银丝和气泡,PC在室温下具有相当大的强迫高弹形变能力。
(2) Ndlela ya Phosgen leyilandzelaka
Phosgen i xihlori xa aksil,naswona i mintirho leyi rharhanganeke, leyi nga thlela yihlanganisiwa hi tidyondzo ta Hyxyl. Nhlangano wa tidyondzo taxibhakabhaka hi ku tirhisa vutshila bya swilo. Bifenool A namati-nkulu ya moya wa Nhlayo, byi hlanganisiwa ku hlamusela ndlelayo ya moya wokarhi wa ngati, na kuhlanganisa na vuxokoxoko byakhale, bya xibhakabhaka ku fana na xihloromethane. Athini (kufanana tetrabutymonium Bromide) yitirhisiwa tani hi muhlovo wa swiyengeeka 50 degree . Kuhlamusela matshamele hikwalaho ka xiyimo xa mati,na ku cinca loko ku langutela swifaniso eka xiyimo xa mati. Ndlelaya tidyondzo ta ikhonomi, ngopfu ngopfu eka ndlela leyilandzeleke.
Ku hlahluva rivoningo inxaxamelo lowu nga kotiki ku hava tinomboro leti ringanaka namintlawa yin'wana. Hi ku angarhela, kukhava kuhlahluva ka phoscieneku sivela nxaxamelo wa swilo eka moya. Nhlayo-nkulu yo tala yaendla leswi endlaka leswaku a ya tinxaka ta manguva lawa yi endlamathlarhi. The purity re of bisphenol A for polycarbonateis high, with specific specifications, and it is not suitable tocontain mono phenol and tri phenol. Otherwise, high molecularweight polycarbonate cannot be obtained or cross-linking mayoccur.
Pfala xiyimiso
Khompuyuta yingava ku hlangana,ku pfapfarhuta, swikombisa, mihlovo yo hambana hambana. Ndzhaku kohumelela, wu endliwa leswaku mihlovo yin'wana na mihlovo yo leha,naswona ndzhawu leyi ngahava mihlovo yo tsandzeka kwalomu ka0.02%.