New synthetic Ni-talc was used as filler in the synthesis of polyurethane (PU) nanocomposites by in situ polymerization and to emphasize the contribution of the new material compared with natural talc. Good dispersion of Ni-talc was supported by homogeneous green coloration observed in the polymer matrix. X-ray diffraction (XRD) analyses indicate the intercalation of polymeric matrix into the filler layers by the increase in d 001 -spacing value of the Ni-talc for the nanocomposites when compared to the pristine filler. The nanocomposites obtained with synthetic talc showed an improvement in the crystallization temperature and in thermal stability when compared to pure PU and the composite obtained with natural talc. The young modulus of PU/talc materials containing both Ni-talc and natural talc were slight higher than pure PU. As shown by scanning electron microscope (SEM), Ni-talc fillers were well dispersed into the polymeric matrix probably due to the good compatibility of both phases filler/polymer mainly achieved by the filler OH interaction with the urethane group of the polymeric chain.

This work presents the syntheses of PU nanocomposites, by in situ polymerization technique, using different synthetic talcs as inorganic filler. The fillers were obtained from two different hydrothermal treatments and composition (talc-Mg and talc-Ni). For nanocomposites syntheses 3% w/w of synthetic talc were added related to the weight of pure polymer. Samples were characterized by Fourier Transform Infrared Spectroscopy (FTIR), X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), Differential Scanning Calorimetry (DSC) and Thermogravimetric Analysis (TGA) to understand the influence of the fillers syntheses and composition in morphological and thermal properties of the obtained nanocomposites. When talc-Ni was used as filler, the resulting nanocomposite was intercalated while with talc-Mg was exfoliated into the polyurethane matrix. Both fillers have increased the thermal properties of the polymer, but the exfoliated nanocomposite provided higher thermal stability.

Two new synthetic silico-metallic mineral particles like TOT-TOT swelling interstratified (SSMMP) produced with distinct hydrothermal processes (talc 7 h/315°C and talc 24 h/205°C) were used to synthesize polyurethane nanocomposites by in situ polymerization technique. These fillers were added in a range of 0.5-5 wt% related to the mass of the pure polymer. The dispersion and interaction between the fillers and the polymeric matrix were evaluated by Fourier transform infrared spectroscopy, X-ray diffraction and scanning electron microscopy. The X-ray analysis indicated that the synthetic SSMMP are well dispersed/or exfoliated into the polymer matrix. The high surface area of the synthetic SSMMP was significant for the increase in the crystallinity and thermal properties of the nanocomposites. In the case of Young's modulus, for nanocomposites PU/SSMMP 24 h and the pristine PU, a similar behavior was observed. However, for the nanocomposites PU/SSMMP 7 h, an increase in the Younǵs modulus values until 3 % of filler addition when compared to pure PU was noticed. The creep-recovery test showed that both SSMMP behave as a mechanical restraint of the polyurethane chains. The results evidenced the importance of the SSMMP syntheses conditions to obtain nanocomposites with desired properties.

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Optically transparent membranes from bacterial cellulose (BC)/polycaprolactone (PCL) have been prepared by impregnation of PCL acetone solution into dried BC membranes. UV-Vis measurements showed an increase on transparency in BC/PCL membrane when compared with pristine BC. The good transparency of the BC/PCL can be related to the presence of BC nanofibers associated with deposit of PCL nano-sized spherulites which are smaller than the wavelength of visible light and practically free of light scattering. XRD results show that cellulose type I structure is preserved inside the BC/PCL membrane, while the mechanical properties suggested indicated that PCL acts as a plasticizer for the BC membrane. The novel BC/PCL membrane could be used for preparation of fully biocompatible flexible display and biodegradable food packaging.