Thermoplastic polyurethanes from renewable resources: effect of soft segment chemical structure and molecular weight on morphology and final properties

Abstract

The effect of soft segment molecular weight and chemical structure on the morphology and final properties of segmented thermoplastic polyurethanes containing various hard segment contents has been investigated from the viewpoint of the degree of microphase separation. Vegetable oil‐based polyesters and corn sugar‐based chain extender have been used as renewable resources. The synthesis has been carried out in bulk without catalyst using a two‐step polymerization process. Physicochemical, thermal and mechanical properties, and also morphology, have been studied using Fourier transform infrared spectroscopy, differential scanning calorimetry, dynamic mechanical analysis, atomic force microscopy, X‐ray diffraction and mechanical testing. Chemical structure and molecular weight of polyols strongly affect the properties of the synthesized segmented thermoplastic polyurethanes. An increase in soft segment molecular weight leads to an increase of the degree of soft segment crystallinity and microphase separation, thus giving enhanced mechanical properties and higher thermal stability. Copyright © 2012 Society of Chemical Industry

Design of Triple-Shape Memory Polyurethane with Photo-cross-linking of Cinnamon Groups

“…And below room temperature the storage modulus increases with the increasing of hard segments, owing to the reduced chain motion with higher hard segments and a high crystallinity of soft segment at lower temperature. 42 The continuous decrease in E′ until T m of soft segments, where a sharp decrease is observed, is related to the melting transition temperature of soft segment. 42 The SMPs with a higher storage modulus would possess a faster recovery ratio.…”

“…42 The continuous decrease in E′ until T m of soft segments, where a sharp decrease is observed, is related to the melting transition temperature of soft segment. 42 The SMPs with a higher storage modulus would possess a faster recovery ratio. 41 From the above discussion of gel fraction, we can find that TSMPU (10:9:1) could not form the crosslinked structure under the UV irradiation, and thus it is not discussed under the below discussion.…”

“…The crosslinked structure in TSMPU prevent the crystallization and movement of soft segments. 42 The SEM micrographs of the PCLU and TSMPU in Figure S2C, D in the Supporting Information were taken from the cross-sections by freeze fracture, and a homogeneous matrix that contains a dispersed crystallites phase can be observed. There is a distinct difference between the PCLU and TSMPU.…”

Effect of sisal fiber filler on thermal properties of bio-based polyurethane composites

“…20°C (ca. 0°C) indicated on the soft segments melting temperature, Tm SS [26]. These points are strongly connected with peaks visible in the variation of Tan d versus temperature graph (Fig.…”

Structure analysis and thermal degradation characteristics of bio-based poly(propylene succinate)s obtained by using different catalyst amounts

“…In consequence, the mobility of the amorphous chains would be restricted by neighbouring crystals. In the sequel, the glass transition temperature will be lower and the melting point will be higher [29,30]. Figure 5 shows the results of the differential scanning calorimetry measurements of two of the prepared bio-based polyester polyols.…”