Surface and thermomechanical characterization of polyurethane networks based on poly(dimethylsiloxane) and hyperbranched polyester

Two series of polyurethane (PU) networks based on Boltorn® hyperbranched polyester (HBP) and hydroxyethoxy propyl terminated poly(dimethylsiloxane) (EO-PDMS) or hydroxy propyl terminated poly(dimethylsiloxane) (HPPDMS), were synthesized. The effect of the type of soft PDMS segment on the properties of PUs was investigated by Fourier transform infrared spectroscopy (FTIR), contact angle measurements, surface free energy determination, X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), atomic force microscopy (AFM), dynamic mechanical thermal analysis (DMTA) and differential scanning calorimetry (DSC). The surface characterization of PUs showed existence of slightly amphiphilic character and it revealed that PUs based on HP-PDMS have lower surface free energy, more hydrophobic surface and better waterproof performances than PUs based on EO-PDMS. PUs based on HPPDMS had higher crosslinking density than PUs based on EO-PDMS. DSC and DMTA results revealed that these newlysynthesized PUs exhibit the glass transition temperatures of the soft and hard segments. DMTA, SEM and AFM results confirmed existence of microphase separated morphology. The results obtained in this work indicate that PU networks based on HBP and PDMS have improved surface and thermomechanical properties

The validity of the index of vulnerable homes : evidence from consumers vulnerable to energy poverty in the UK

Energy poverty is a multidimensional issue, and this means that it is difficult to understand the different levels of vulnerability to this phenomenon and its relationship with households’ quality of life. This paper presents the validation of an innovative index for the analysis of vulnerability to energy poverty according to monetary, energy and thermal comfort factors: The Index of Vulnerable Homes (IVH). The IVH goes beyond the use of single self-reported indicators of thermal comfort, and instead uses the adaptive thermal-comfort model defined in the normative UNE EN 15251:2007 to assess thermal comfort in relation to energy poverty. Furthermore, it has the potential to evaluate societal impacts of current energy poverty policies by providing the economic analysis of different situations of vulnerability. The IVH is validated by comparing its results to those obtained from a survey conducted in a small-scale study undertaken in Salford, UK. To this end, evidence from households living in terraced houses built before 1980 is used to analyse health status in terms of vulnerability to energy poverty vulnerability according to their monetary situation and the characteristics of the dwelling. In the end, the results show good agreement between both the IVH’s assessment and households’ evidence, leading to consider the IVH as a suitable approach to understanding different levels of vulnerability to energy poverty