Effect of tetrasilanolphenyl silsesquioxane on properties of sorbitol derivative-nucleated polypropylene cast films

Abstract

Nucleating agents cause an increase in crystallization temperature, making the production of highly oriented films much more difficult. In this study, a nucleating system composed of 1,3:2,4-bis(3,4-dimethylbenzylidene) sorbitol (DMDBS) and tetrasilanolphenyl silsesquioxane (phPOSS) was used to modify isotactic polypropylene (iPP). Oriented films characterised by different draw drown ratios (4.8, 9.7, 14.5) were prepared and analysed. Their mechanical properties, coefficient of friction, thermal properties, and structure as well as optical properties such as gloss, haze, and transparency, were also determined. The macromolecular orientation of films was tested by polarised light Fourier transform infrared spectroscopy. The proposed nucleating system provides films with superior mechanical and optical properties, which are accompanied by high orientation ability. The application of DMDBS and phPOSS allowed a 26% increase in penetration load at break and Young modulus by 70% compared to iPP. It can be assumed that DMDBS/phPOSS system is an efficient modifier for polypropylene film production.

Effect of Shear Stress during Processing on Structure, Morphology, and Properties of Isotactic Polypropylene Nucleated with Silsesquioxane-Based β-Nucleating Agent

“…Following this line of research, several works proved that the simultaneous introduction of nucleants promoting crystallization in the forms α and β with the participation of silsesquioxane led to the formation of a reactive or physically-mixed nucleating system. As a result, it is possible to increase its effectiveness [ 39 , 40 , 41 ] or control the structure to obtain specific functional or processing characteristics of iPP [ 42 , 43 , 44 ].…”

“…However, this previous work did not consider the complex influence of crystallization conditions, which can significantly alter the growth of the hexagonal phase of polypropylene. Therefore, this study was designed to investigate the diverse and often opposite effects of shear flow, the presence of polypropylene β-phase crystallization-promoting nucleants [ 42 ], and the complex behavior caused by silsesquioxanes during polymer crystallization in shearing conditions [ 28 ]. This work presents the physical modification of polypropylene with N 2 ,N 6 -dicyclohexylnaphthalene-2.6-dicarboxamide, and silsesquioxane-based NAs.…”