本文選題：聚丙烯 + 溶脹��； 參考：《東北石油大學(xué)》2017年碩士論文

【摘要】：高熔體強度聚丙烯研究開始于上世紀八十年代,高熔體強度聚丙烯的熔體強度高并且具有明顯的應(yīng)變硬化現(xiàn)象,從而聚丙烯在擠出涂布、發(fā)泡和熱成型中得到了廣泛的應(yīng)用,因此對于高熔體強度聚丙烯的研究具有重要的意義。本課題的研究目標是制備高熔體強度聚丙烯,掌握制備高熔體強度聚丙烯的相關(guān)技術(shù)和工藝過程。課題研究的關(guān)鍵是在聚丙烯大分子主鏈上引入適當?shù)慕宦?lián)結(jié)構(gòu)和長支鏈結(jié)構(gòu)以提高熔體強度以及對降解反應(yīng)的控制。本文采用溶劑浸漬協(xié)助PP固相交聯(lián)接枝法制備高熔體強度聚丙烯,以乙醚為溶脹劑,二乙烯基苯(DVB)為單體,過氧化苯甲酰(BPO)為引發(fā)劑,可以顯著提高聚丙烯的熔體強度,考察了溶脹劑用量、溶脹時間、溶脹溫度、單體和引發(fā)劑用量、界面劑用量、粒徑、反應(yīng)時間和反應(yīng)溫度等因素對改性產(chǎn)品的熔體強度、熔體流動速率和凝膠含量的影響,并采用TG、FTIR、PLM、XRD和DSC等對產(chǎn)品進行了表征。研究結(jié)果表明,當按照PP:DVB:BPO的質(zhì)量比為100:0.2:0.03投料,用20 ml溶脹劑在30℃溶脹10 h后,再在100℃反應(yīng)2 h獲得產(chǎn)物的熔體強度最大值(6.4 kPa.s),比原PP的MS提高11倍,與未溶脹的相比,MS提高了4.9 kPa·s,說明使用溶劑浸漬協(xié)助PP固相接枝過程中,引發(fā)劑和單體進入聚丙烯顆粒內(nèi)部可以有效提高產(chǎn)物的MS,彌補了傳統(tǒng)固相反應(yīng)主要在PP顆粒表面進行,單體分布不均勻的缺點。紅外結(jié)果表明,DVB單體成功接枝到PP主鏈上;通過DSC和PLM表征分析可知,支化交聯(lián)結(jié)構(gòu)促進了結(jié)晶作用,使結(jié)晶溫度變高,結(jié)晶度變小。球晶變小,數(shù)量變多,邊界變模糊;熱重分析可知,與純PP相比,改性產(chǎn)品的熱穩(wěn)定性有所提高;通過XRD表征可知,改性后的高熔體強度聚丙烯沒有改變其晶型,仍與普通聚丙烯相同為單斜晶系的α晶型結(jié)構(gòu)。其次采用雙單體1,6-己二醇二丙烯酸酯(HDDA)-DVB成功制備了高熔體強度聚丙烯,考察了在體系中共單體HDDA含量對改性聚丙烯的凝膠含量、熔體流動速率和熔體強度的影響并對改性后產(chǎn)品進行了表征。當w(DVB)/w(HDDA)=1/2時,熔體強度最大,達到10 kPa·s;在不同HDDA用量下,改性后的熔體強度隨著HDDA用量的增加而增大,而對凝膠含量的影響不大。紅外表征可知,雙單體HDDA和DVB成功接枝到PP主鏈上;通過熱重表征可知,體系中HDDA單體的加入使改性PP的熱穩(wěn)定性進一步提高。通過XRD表征可知,體系中HDDA單體的加入沒有改變產(chǎn)品的晶型,其晶型與普通聚丙烯相同,即均為單斜晶系的α晶型結(jié)構(gòu)。
[Abstract]:The research of high melt strength polypropylene began in 1980s. The melt strength of high melt strength polypropylene is high and has obvious strain hardening phenomenon, so polypropylene has been widely used in extrusion coating, foaming and hot forming. Therefore, the study of high melt strength polypropylene is of great significance. The purpose of this paper is to prepare high melt strength polypropylene and to master the relevant technology and process of preparing high melt strength polypropylene. The key of the research is to introduce appropriate cross-linking structure and long branched chain structure into the main chain of polypropylene macromolecule in order to improve the melt strength and control the degradation reaction. In this paper, high melt strength polypropylene was prepared by solvent impregnation assisted by solid phase crosslinking grafting of PP. The melt strength of polypropylene was significantly improved by using ether as swelling agent, divinylbenzene (DVB) as monomer and benzoyl peroxide (BPO) as initiator. The effects of the amount of swelling agent, swelling time, swelling temperature, amount of monomer and initiator, amount of interfacial agent, particle size, reaction time and reaction temperature on the melt strength, melt flow rate and gel content of the modified product were investigated. The products were characterized by XRD and DSC. The results showed that when the mass ratio of PP: DVB: BPO was 100: 0.2: 0.03, the maximum melt strength (6.4 KPA 路s) of the product was obtained after swelling at 30 鈩，

本文編號：2108650