Nowadays,polymer foams have a wide application area due to their light weight,emphasizing resistance to impact,high thermal insulation and damping properties,among others.So,automotive,packing industry,electronic,aero...Nowadays,polymer foams have a wide application area due to their light weight,emphasizing resistance to impact,high thermal insulation and damping properties,among others.So,automotive,packing industry,electronic,aerospace,building construction,bedding and even medical applications are some of the fields where polymer foams are applied.Foams can be classified as open and closed:Closed-cell foam is provided with tiny and discrete pockets of gas,each one totally enclosed within polymer walls;open cell foam has tiny cells which are not completely closed.In this work,LDPE(low density polyethylene)resin foamability was investigated after exposure to ionizing radiation(gamma),at 5,10 and 15 kGy.Characterizations included:melt flow index,melt strength and scanning electron microscopy.展开更多
Hydrogels for wound dressings are usually developed for contact surfaces where mechanical properties are conveniently required.In this sense nanocomposite hydrogels based on PVAl(poly(vinyl alcohol))and PVP(poly(N-2-v...Hydrogels for wound dressings are usually developed for contact surfaces where mechanical properties are conveniently required.In this sense nanocomposite hydrogels based on PVAl(poly(vinyl alcohol))and PVP(poly(N-2-vinil-pirrolidone))containing 0.5-1.5 wt%of the synthetic laponite RD clay were prepared by a gamma radiation process and compared with similar membranes composed separately of PVP or PVAl.This study aimed to evaluate the effect of clay on the properties and the differences of the polymer blend instead of a unique polymer.The morphology of the hydrogels was evaluated by spectrometric techniques using XRD(X-ray diffraction),SEM(scanning electron microscopy),swelling assay,and FTIR(infrared spectroscopy).The swelling kinetics at 22℃and the mechanical properties by a tensile test comprised the structural properties that were assessed.The results showed PVA/PVP network depends directly on the clay concentration in the nanocomposite hydrogels.The blend PVP/PVAl proved to have potentially efficient mechanical properties for drug delivery in the treatment of wounds.展开更多
文摘Nowadays,polymer foams have a wide application area due to their light weight,emphasizing resistance to impact,high thermal insulation and damping properties,among others.So,automotive,packing industry,electronic,aerospace,building construction,bedding and even medical applications are some of the fields where polymer foams are applied.Foams can be classified as open and closed:Closed-cell foam is provided with tiny and discrete pockets of gas,each one totally enclosed within polymer walls;open cell foam has tiny cells which are not completely closed.In this work,LDPE(low density polyethylene)resin foamability was investigated after exposure to ionizing radiation(gamma),at 5,10 and 15 kGy.Characterizations included:melt flow index,melt strength and scanning electron microscopy.
文摘Hydrogels for wound dressings are usually developed for contact surfaces where mechanical properties are conveniently required.In this sense nanocomposite hydrogels based on PVAl(poly(vinyl alcohol))and PVP(poly(N-2-vinil-pirrolidone))containing 0.5-1.5 wt%of the synthetic laponite RD clay were prepared by a gamma radiation process and compared with similar membranes composed separately of PVP or PVAl.This study aimed to evaluate the effect of clay on the properties and the differences of the polymer blend instead of a unique polymer.The morphology of the hydrogels was evaluated by spectrometric techniques using XRD(X-ray diffraction),SEM(scanning electron microscopy),swelling assay,and FTIR(infrared spectroscopy).The swelling kinetics at 22℃and the mechanical properties by a tensile test comprised the structural properties that were assessed.The results showed PVA/PVP network depends directly on the clay concentration in the nanocomposite hydrogels.The blend PVP/PVAl proved to have potentially efficient mechanical properties for drug delivery in the treatment of wounds.
