Mechanically Robust Hybrid POSS Thermoplastic Polyurethanes with Enhanced Surface Hydrophobicity.

Xiuhuan Song,Zibiao Li,Tianduo Li,Xiaoxiao Zhang,Hong Chi

doi:10.3390/polym11020373

Abstract

A series of hybrid thermoplastic polyurethanes (PUs) were synthesized from bi-functional polyhedral oligomeric silsesquioxane (B-POSS) and polycaprolactone (PCL) using 1,6-hexamethylene diisocyanate (HDI) as a coupling agent for the first time. The newly synthesized hybrid materials were fully characterized in terms of structure, morphology, thermal and mechanical performance, as well as their toughening effect toward polyesters. Thermal gravimeter analysis (TGA) and differential scanning calorimetry (DSC) showed enhanced thermal stability by 76 °C higher in decomposition temperature (Td) of the POSS PUs, and 22 °C higher glass transition temperature (Tg) when compared with control PU without POSS. Static contact angle results showed a significant increment of 49.8° and 53.4° for the respective surface hydrophobicity and lipophilicity measurements. More importantly, both storage modulus (G’) and loss modulus (G’’) are improved in the hybrid POSS PUs and these parameters can be further adjusted by varying POSS content in the copolymer. As a biodegradable hybrid filler, the as-synthesized POSS PUs also demonstrated a remarkable effect in toughening commercial polyesters, indicating a simple yet useful strategy in developing high-performance polyester for advanced biomedical applications.

Highlights

Polyurethane (PU) is a kind of thermoplastic elastomeric polymer, consisting of both hard and soft segments
The soft segments are usually composed of flexible polyester or polyether and the hard segments are usually composed of diisocyanates with benzyl structure [1]
The peaks of 3,13-dihydrooctaphenyl bi-functional polyhedral oligomeric silsesquioxane (B-polyhedral oligomeric silsesquioxanes (POSS)) appeared at 0.38 ppm (b), 3.41 ppm (e) and 7–8 ppm (f) were assigned to the protons of –Si–CH3, –CH2 –OH and phenyl groups, respectively

Summary

Introduction

Polyurethane (PU) is a kind of thermoplastic elastomeric polymer, consisting of both hard and soft segments. The soft segments are usually composed of flexible polyester or polyether and the hard segments are usually composed of diisocyanates with benzyl structure [1]. Such alternating structure endows PU with good shape recovery property as well as high resistance to abrasion, stretchability [2], high adhesiveness and eases of processability because the hard phase can form a force center which holds the soft phase and retains the original shape [3]. Despite the advantages as mentioned above, PU does show several drawbacks including low mechanical strength and short shelf-life. The fillers can be graphene [5,6] small molecules [7], Polymers 2019, 11, 373; doi:10.3390/polym11020373 www.mdpi.com/journal/polymers

Methods

Results

Conclusion