17. Polypropylene composites with ultrahigh low-temperature toughness by tuning the phase morphology
作者：Zhong-Guo Zhao, Sheng-Tai Zhou, Li-Jun Quan, Wei-Long Xia, Qian Fan, Peng-Hui Zhang, Yan-Hui Chen*,
關(guān)鍵字：Isotactic polypropylene， Carbon nanotubes， Ethylene-octene multiblock copolymer，Low-temperature toughness，Co-continuous phase morphology
論文來(lái)源：期刊
具體來(lái)源：Industrial & Engineering Chemistry Research, 2022, 61, 41, 15240-15248.
發(fā)表時(shí)間：2022年
等規(guī)聚丙烯(iPP)是一種常用的熱塑性工程塑料材料，在過(guò)去的幾十年里被廣泛的用來(lái)制造購(gòu)物袋、管材、農(nóng)用薄膜以及其他的工業(yè)應(yīng)用。然而，隨著使用溫度的降低，會(huì)極大地影響聚丙烯的韌性，會(huì)導(dǎo)致其由韌性到脆性的轉(zhuǎn)變，造成聚丙烯復(fù)合材料力學(xué)性能的惡化，這也大大的限制了聚丙烯管材在極端寒冷環(huán)境下的進(jìn)一步應(yīng)用。課題組針對(duì)聚丙烯耐寒問(wèn)題，通過(guò)對(duì)聚丙烯復(fù)合材料內(nèi)部微結(jié)構(gòu)的調(diào)控，使iPP/0.1wt% β-NAs/30 wt% OBC共混體系具有超高的低溫沖擊韌性。與純iPP相比，在僅添加0.5wt% CNTs時(shí)，可使iPP/0.1wt% β-NAs/30 wt% OBC復(fù)合材料在使用溫度為-20℃時(shí)，低溫沖擊韌性高達(dá)52.2kJ/m2，其中沖擊強(qiáng)度增加幅度約2386%。通過(guò)CNTs添加含量的調(diào)控可使β-iPP復(fù)合材料形成共連續(xù)的相形態(tài)，這是復(fù)合材料在低溫環(huán)境下能顯著增強(qiáng)應(yīng)力消散的關(guān)鍵。此外，CNTs在iPP和OBC相之間的分布以及β-NAs和OBC誘導(dǎo)的自增韌β-晶體的存在將有助于進(jìn)一步提高iPP基復(fù)合材料的低溫沖擊強(qiáng)度。本課題組提出了一種切實(shí)可行的增強(qiáng)復(fù)合材料低溫韌性的策略，擴(kuò)大了其在工業(yè)領(lǐng)域的應(yīng)用潛力。
Isotactic polypropylene (iPP), as a common engineering thermoplastic material, is widely selected to manufacture shopping bag, pipe, agricultural film and other industrial applications inpast decades. However, decreasing the using temperature can induce thetransition from ductile to brittle failure of iPP, thereby inducing the dramatic deterioration of mechanical properties. Therefore, the poor low-temperature impact strength of iPP (especially below glass transition temperature, Tg) largely restricts its further applications in frigid environment such as outdoor pipelines. To broaden the potential application of isotactic polypropylene (iPP) in low-temperature conditions, iPP/0.1 wt% β-nucleated agent/30 wt% ethylene-octene multiblock copolymer (iPP/0.1 wt% β-NAs/30 wt% OBC) blends were endowed with ultrahigh low-temperature impact toughness by adjusting the nanotubes (CNTs) content. In comparison with pure iPP, the low-temperature impact toughness of iPP/0.1 wt% β-NAs/30 wt% OBC composites with only adding 0.5 wt% CNTs reached as high as 52.2 kJ/m2 at -20 ℃, of which the increment of impact strength was about 2386%. This optimum content of CNTs gave rise to a co-continuous phase morphology in β-nucleated iPP composites which turned out to be the key to the greatly enhanced stress dissipation, even at low-temperature environment. In addition, the distribution of CNTs between iPP and OBC phase, and the presence of self-toughened β-crystals that were induced by β-NAs and OBC contributed to improving the low-temperature impact strength of iPP-based composites. A feasible strategy is developed to substantially reinforce the low-temperature toughness of iPP-based composites, which expands their potential applications in industrial sectors.
