Search

Amorphous cellulose particles, obtained through a solvent-free mechano-chemical process, have been tested for the first time as a potential filler for biodegradable composites based on poly(ɛ-caprolactone) (PCL). Commercial cellulose fibers have been also tested for comparison. An effective interfacial strategy based on a compatibilizing agent, a modified PCL, has been used to improve the polymer/filler interfacial adhesion. Composites have been tested through physico-mechanical characterizations and soil burial degradation tests, in order to evaluate the influence of cellulose structure and morphology and polymer/filler interfacial adhesion on the final properties of the realized materials. The use of the amorphous cellulose particles combined with the presence of a suitable interfacial agent has allowed to modulate relevant technological properties of the realized composites, such as tensile and thermal properties, water absorption, water vapor transmission rate and biodegradation kinetic. [ABSTRACT FROM AUTHOR]

Biodegradable poly(vinyl alcohol) (PVOH) based foams were prepared through an ecofriendly methodology. Different amount of recycled multilayer cartons (MC), composed of cellulose and low-density polyethylene (80/20 wt/wt), were added as a direct cellulose source to PVOH. Foams were realized through a modified overrun process without using chemical agents or promoting chemical reactions. In particular, the air entrapped during the high-speed mixing of the PVOH/MC water dispersion was able to create a porous morphology. The effects of the addition of MC on microstructure, swelling behavior, and mechanical and thermal properties of foams were investigated. Materials were characterized by a dual-pore structure. Improvements of the swelling behavior, mechanical properties, and thermal stability were recorded as a function of MC content. These findings can be considered as a result of a good interaction between filler and polymer. [ABSTRACT FROM PUBLISHER]

With the aim at controlling cellulose degradation phenomena, the natural aging of Whatman paper samples was simulated through different artificial aging processes: thermal oxidation in air at constant temperature, photo-oxidation under Xenon arc lamp, accelerating ageing in climatic chamber, and chemical oxidation with sodium methaperiodate. The cellulose degradation was studied by means of viscosimetric, Fourier transform infrared spectroscopy (FTIR), and wide angle X-ray scattering (WAXS) techniques together with thermogravimetric (TGA), mechanical, and optical analyses. All the treatments carried out were found to significantly modify paper structure and properties, the extent of the deterioration effects depending upon the aging kind. Direct correlations were, nevertheless, assessed among level of cellulose molecular degradation, formation of carboxyl, and/or carbonyl groups and paper strain at break. [ABSTRACT FROM AUTHOR]

With the aim of identifying the most suitable commercial water dispersed polyacrylates to be used in the conservation and restoration field, the properties of four commercial polymers were compared with those shown by Primal AC33, a product made and commercialized by Rohm and Haas, widely used as a consolidating and adhesive agent for art works, and nowadays out of production. Chemical, molecular, thermal, mechanical and optical investigation techniques were applied on films obtained from the polymer water dispersions cast at room temperature. Selected polymers were characterized before and after artificial aging under a xenon-arc lamp in order to determine their photooxidative stability. It was found that Acrilem IC15, among the selected products, was the material with improved physico-chemical properties and photooxidative stability with respect to that shown by the discontinued Primal AC33. [Copyright &y& Elsevier]

Scattone A, Serio G, Marzullo A, Nazzaro P, Corsi F, Cocca M P, Mattoni M, Punzi A, Gentile M, Buonadonna A L & Pennella A (2012) Histopathology 60, 472-481 High Wilms' tumour gene (WT1) expression and low mitotic count are independent predictors of survival in diffuse peritoneal mesothelioma Aims: To evaluate the use of the Wilms' tumour gene (WT1) marker and histomorphological parameters as indicators of prognosis in malignant peritoneal mesothelioma (MPM). Methods and results: Histological samples of 31 MPM were stained immunohistochemically for the WT1 protein. The results were quantified by recording the number of stained nuclei, and then correlated with patient survival. Statistical correlation was evaluated for tumour histotype, mitotic count (MC), nuclear grade (NG), necrosis, lymphoid response (grade of inflammation) and desmoplasia with regard to survival. High-grade histology (solid epithelioid, pure sarcomatoid or biphasic tumours), high NG, MC more than five per 10 per high-power field (HPF), necrosis and desmoplasia were associated with a significantly worse prognosis. Patients with MPM with low WT1 expression (≤25% of positive cells) survived for a significantly shorter time compared to those with high WT1 expression (>25% of positive cells) ( P = 0.0001). The 50% survival time of subjects with low WT1 expression was 2.9 months [95% confidence interval (CI): 2.05-3.71] versus 31.5 months (95% CI: 20.4-42.5) for those with high WT1 expression. On multivariate analysis, WT1 and MC were found to be associated independently with survival ( P = 0.002; P = 0.005, respectively). Conclusions: Our study suggests that low WT1 expression and high MC may be indicative of an unfavourable prognosis in patients with advanced malignant peritoneal mesothelioma. [ABSTRACT FROM AUTHOR]

• The cellulose is used as reactive filler in the synthesis of polyurethane foams. • The cellulose is used to tune the chemico-physical and mechanical properties of foams. • Two topologies of cellulose were used: crystalline and amorphous. • A reduction of the thermal conductivity of 33% is obtained with amorphous cellulose. • The amorphous cellulose modifies the mechanical behavior from rigid to semi-rigid. Cystalline-Cc and ultra-milled Amorphous-Ca cellulose were used as reactive filler to tune the performances of composite polyurethane-cellulose-foams, PUC. The effect of Cc and Ca on chemo-physical and mechanical properties of PUC was analysed through FTIR, morphological analysis, thermal conductivity and compression measurements. FTIR results show that, both Cc and Ca react with isocyanate through the OH functional groups contributing to the formation of a tough cellulose-polyurethane network. Morphological observations show that the addition of both Cc and Ca induces a decrease of average cell-size compared to the pristine-PU, thus confirming that they act as nucleating agent. In addition, the better dispersion of the Ca in the polyol, with respect to Cc induces, a finer cell leading to a reduction of the thermal conductivity around 33 % (for the composite loaded with 20 %wt-Ca) with respect to pristine-PU. Finally, the addition of Ca highly reactive modifies the mechanical behaviour from rigid-brittle to semi-rigid. [ABSTRACT FROM AUTHOR]

• UV-induced degradation lowers the corrosion inhibitor ability of benzotriazole. • Mesoporous silica nanocarriers protect benzotriazole from photodegradation. • High anticorrosion efficacy of nanocomposite coatings even after UV exposure. Corrosion inhibitors are largely exploited for the development of highly performing polymeric active coatings. One of the major drawbacks, however, relies in their UV sensitivity, which may compromise their ability to effectively prevent corrosion processes. This issue is particularly relevant in the field of cultural heritage preservation, in which polymeric active coating which are able to ensure a reliable and long-lasting protection against corrosion are highly needed. Besides proving that UV-induced photodegradation impressively lowers the corrosion inhibition ability of benzotriazole (BTA), in the present work we show that this phenomenon can be largely prevented by exploiting inorganic nanocarriers. More specifically, BTA molecules loaded into functionalized mesoporous silica nanoparticles are preserved from photodegradation and released in the host coating only in the presence of acid-related external stimuli. Accelerated corrosion tests carried out on a commercial acrylic-based coating containing engineered mesoporous silica nanoparticles loaded with BTA demonstrated that the developed system possesses an excellent anticorrosion ability. [ABSTRACT FROM AUTHOR]

Composites based on poly(butylene succinate- co -butylene adipate) (PBSA) containing amorphized and crystalline cellulose reinforcements have been prepared and characterized. In order to improve the polymer/filler interfacial adhesion, an efficient compatibilizing agent has been synthesized by chemical modification of PBSA and characterized by FT-IR, FT-NIR and 1 H NMR spectroscopy. Uncompatibilized and compatibilized composites have been tested through morphological, mechanical, calorimetric and thermogravimetric analysis. Moreover, water vapor permeability and biodegradation kinetics of composites have been investigated. The addition to PBSA of cellulose fillers differing from each other by crystallinity degree and morphology, and the use of a compatibilizing agent have allowed modulating tensile and thermal properties, water vapor transmission rate and biodegradation kinetic of the composites. [ABSTRACT FROM AUTHOR]