ABSTRACT
Photodegradation is one of the key factors that affect bamboo material application in the exterior environment. Photo radiation will cause chemical degradation, discoloration and cracks on the bamboo surface, thus resulting in weakened strength. The study imitated the accelerated weathering effect of Moso bamboo in sunlight by using UV 313 light. Results showed that after UV irradiation, lignin content decreased sharply. Lignin degradation products are commonly rich in double bonds conjugated with benzene rings; they absorb UV light and shift surface spectral absorbency from the visible to the UV region and play an important role in the first stage of reddish-yellow discoloration. The photochemical reactions were very rapid at the beginning and then slowed down after one week. The degraded products covered the surface and protected the inner layer from further degradation. The surface colour turned grey and lighter with erosion of degradation products when the experimental time was extended.
ABSTRACT
Acorn starch was used as the main material. Thermoplastic acorn starch (TPAS) and binary composites of thermoplastic acorn starch(TPAS)/Polycaprolactone (PCL) were prepared by hot-melt extrusion method. The effects of different plasticizers such as ethylene glycol, glycerol, monoethanolamine, iminobisetnanol and triethanolamine on molecular structure of samples were studied by FTIR and XRD analysis. In addition, the effects of different plasticizing system on molecular structure and mechanical properties of composites were also studied. The results showed that the addition of plasticizers changed the inter-molecular structure, and glycerol-based TPAS/PCL composites showed favorable mechanical properties.
