The starch-based foam was preprared by moulding process and studied the effects on the density, mechanical properties, hardness and water absorption capacity of the foams with different polyvinyl alcohol (PVA) contents. The microstructure and crystallization of the foam was observed through the scanning electron microscopy (SEM) and X-ray diffraction (XRD). The results showed that the addition of PVA could better improve the material mechanical properties, the elongation at break was increased from 15.72% to 113.86% while the hardness was reduced from 37.3 to 16.7. The density of foam reached to the minimum value of 0.261 g/cm3, attaining to the maximum tensile strength of 1.08 Mpa. SEM and XRD showed that the compatility of starch and PVA was very good and the addition of PVA helped to improve the bubble distribution of foam and inhibit the retrogradation of starch granules.

Concrete is a typical heterogeneous porous media material, but the influence of the heterogeneity of concrete on coupled temperature and moisture transfer is rarely involved in the present numerical methods. Thus, the research direction on the coupled temperature and moisture transfer with damage evolution of the heterogeneous material will be greatly helpful to understand the coupling mechanism. This paper firstly presented the purpose of the study on the coupled temperature and moisture transfer in concrete, and then offered a literature review of the development of this theory. To launch the elaboration of this topic, three relative important parts were presented separately in this paper. (1)The comprehensive theory of porous media heat and mass transfer. (2)The development of the coupled temperature and moisture transfer on mesoscopic scale. (3) The numerical simulation methods of the coupled temperature and moisture transfer. And then the influence of damage on the parameters of temperature field and humidity field was pointed out, which would be a valuable research field.

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