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Novel sandwich composites made of syntactic foam core and paper skin were developed as potential building materials. Interface bonding between core and skin was controlled by varying starch content. Two different microsphere size groups were employed for syntactic foam core manufacturing based on the pre-mold processing method. Properties of skin paper with starch adhesive on were found to be affected by drying time of starch adhesive. Mechanical behavior of manufactured sandwich composites in relation with properties of constituent materials was studied. Skin paper contributed to increase up to 40% in estimated flexural strength over syntactic foams, depending on starch content in adhesive between syntactic foam core and paper skin. Small microsphere size group for syntactic foam core was found to be advantageous in strengthening of sandwich composites for a given starch content in adhesive. This finding was in agreement with calculated values of estimated shear stress at interface between skin and core. Failure process of the sandwich composites was discussed in relation with load–deflection curves. Cracking of syntactic foam core was detected to be the first event in sandwich composite failure sequence. Hygroscopic behavior of syntactic foam panels was investigated. Moisture content in the foam was measured to be high for high starch content in the foam panels. No significant moisture effect on flexural strength of syntactic foam panels after being subjected to moisture about 2 months was found for both microsphere size groups. However, substantial decrease (28%) in flexural modulus was found for the foam panels made of large microspheres although not much moisture effect was found on that of small microspheres. [ABSTRACT FROM PUBLISHER]

The manufacture of low density paper such as tissue and towel utilizes the creping process that consists of adhesively bonding the paper in wet state onto the surface of a smooth drying cylinder and scraping it off with a blade once dried. In this paper, a mechanics of materials description of the creping process is presented. Based upon previous experimental observations, the mechanism of this creping process is proposed as a periodic debonding with a strength-of-materials failure criterion applied and buckling sequence of an elastic thin film. Numerical calculations show results consistent with experimental data and known industrial observations. Crepe wavelength versus creping angle data from experiments can be satisfactorily reproduced by a reasonable set of values for input parameters to the model. Parametric study shows the adhesive shear strength and the sheet stiffness most significantly affect the crepe wavelength and the creping force. The model provides guidance in understanding and optimizing the creping process to produce high quality products. [ABSTRACT FROM AUTHOR]