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In the frame of the Next Generation Europe program, the EU program to boost after-COVID recovery, the Italian Minister of University and Research has funded a project called Innovative Research Infrastructure for applied Superconductivity (IRIS). New laboratories will be built or upgraded in six poles: Milan (hub of the infrastructure), Genoa, Frascati, Naples, Salerno, and Lecce, to carry out basic research on magnetism and superconducting materials, test of wires, tapes, and large current cables, superconducting magnets construction with advanced instrumentation, power tests of magnets, and a special facility for high current-high voltage superconducting lines. The program will be executed over three years and then will operate for at least 10 years. It includes two first demonstrators: one HTS magnet to be operated at 10–20 K and a superconducting line of 1 GW (40 kA–25 kV) about 140 m long. The demonstrators anticipate the main scope of the investment in the IRIS infrastructure: to support the use of superconductivity for improving sustainability by decreasing the energy consumption without compromising performance. This article describes the global IRIS project.

Innovative Research Infrastructure on applied Superconductivity (IRIS) is a major project to build a research infrastructure in applied superconductivity, recently approved in Italy and led by INFN. As part of this programme, we are currently designing a Green Superconducting Line (GSL), 130 m long and designed to carry 40 kA of current at 25 kV, 1 GW of power, with almost zero dissipation. The article will present the up-to-date conceptual design status for the GSL. The line will eventually be tested in the new facility being prepared by INFN-Salerno and the University of Salerno (Italy).

Peritoneal metastases (PM) have been reported in approximately 1% of patients with metastatic Renal Cell Carcinoma (mRCC). Outcome data are limited due to the rarity of this metastatic site. Therefore, the aim of our study is to describe renal cell carcinoma (RCC) patients with PM treated as per clinical practice.

Electrical energy storage technologies have become a critical aspect of the whole clean energy system, which is fundamentally based on batteries. In the past decades, innovations in batteries changed the appearance of our lifestyle with portable devices. More recently, electrical vehicles have lead the mind toward a promising clean world without fossil fuels. However, minimizing the weight and/or volume of such batteries is the critical design driver, and in the last decade, the idea of moving electric energy accumulation inside structural parts has been proposed and named structural batteries (SBs), in which structural elements should also act as electric energy accumulators. The work on structural batteries to date has mostly involved Li-ion batteries due to their acceptable performance. However, the adoption of Li-ion batteries must face the limited availability of lithium on the earth and safety during their manufacturing and use. These issues encouraged researchers to seek alternative battery systems not having its drawbacks. Zn-ion structural batteries are a promising alternative to lithium-ion batteries in the post-lithium era. Zinc is one of the most abundant elements on the planet and can be found at low price. Zinc-based batteries also have the potential to use lower-cost production procedures because they do not require particular dry room conditions, which means the ability to operate in the air, allowing for large-scale assembly. Although Zn-ion batteries have numerous advantages, the development of Zn-ion structural batteries is still in its early stages (low Technology Readiness Level, TRL), and additional study is required. This review seeks to provide a concise description of current breakthroughs in materials and architecture design, as well as a critical assessment of the performance and limitations of the solutions adopted for zinc-based structural batteries. The difficulties in constructing Zn-ion structural batteries are discussed. This is the first complete examination of these batteries, and it provides an overview of the technology with the aim of promoting future structure battery chemistry research.

Skeletal defects reconstruction, using custom-made substitutes, represents a valid solution to replacing lost and damaged anatomical bone structures, renew their original function, and at the same time, restore the original aesthetic aspect. Rapid prototyping (RP) techniques allow the construction of complex physical models based on 3D clinical images. However, RP machines usually work with synthetic polymers; therefore, producing custom-made scaffolds using a biocompatible material directly by RP is an exciting challenge. The aim of the present work is to investigate the potentiality of 3D printing as a manufacturing method to produce an osteogenic hydroxyapatite-polylactic acid bone graft substitute.

Urothelial carcinoma (UC) is the most frequent malignancy of the urinary tract, which consists of bladder cancer (BC) for 90%, while 5% to 10%, of urinary tract UC (UTUC). BC and UTUC are characterized by distinct phenotypical and genotypical features as well as specific gene- and protein- expression profiles, which result in a diverse natural history of the tumor. With respect to BC, UTUC tends to be diagnosed in a later stage and displays poorer clinical outcome. In the present review, we seek to highlight the individuality of UTUC from a biological, immunological, genetic-molecular, and clinical standpoint, also reporting the most recent evidence on UTUC treatment. In this regard, while the role of surgery in nonmetastatic UTUC is undebated, solid data on adjuvant or neoadjuvant chemotherapy are still an unmet need, not permitting a definite paradigm shift in the standard treatment. In advanced setting, evidence is mainly based on BC literature and retrospective studies and confirms platinum-based combination regimens as bedrock of first-line treatment. Recently, immunotherapy and target therapy are gaining a foothold in the treatment of metastatic disease, with pembrolizumab and atezolizumab showing encouraging results in combination with chemotherapy as a first-line strategy. Moreover, atezolizumab performed well as a maintenance treatment, while pembrolizumab as a single agent achieved promising outcomes in second-line setting. Regarding the target therapy, erdafitinib, a fibroblast growth factor receptor inhibitor, and enfortumab vedotin, an antibody-drug conjugate, proved to have a strong antitumor property, likely due to the distinctive immune-genetic background of UTUC. In this context, great efforts have been addressed to uncover the biological, immunological, and clinical grounds in UTUC patients in order to achieve a personalized treatment.

The aim of this work is the analysis of the suitability of cardanol derivatives as primary plasticizer for polyvinyl chloride (PVC). Cardanol derived plasticizers (CDP) were obtained by acetylation of cardanol, followed by epoxidation of the side chain double bonds. The developed procedures allowed to achieve high yields of acetylated cardanol, whereas plasticizers characterized by different yields of epoxidation were obtained, according to the used synthesis procedure. Rheological analysis was used in order to study the gelation process of PVC plastisols with CDP. A comparison of commercial phthalate and natural derived plasticizers showed that the CDP are characterized by adequate gelation properties, involving a complete absorption of the plasticizers at relatively low temperatures. The gelation properties showed a strong dependence on the yield of the epoxidation. In particular, lower gelation temperatures, higher plasticizer absorption and faster gelation were observed for higher epoxy content in the plasticizer. Finally, ageing tests were performed on soft PVC produced by the CDP. The weight loss of soft PVC with CDP is comparable to that of commercial plasticizers, particularly at high yields of epoxidation.

Graphene stacks/epoxy nanocomposites were produced and characterized in order to analyse the effect of different graphene precursors on cure reaction of a model epoxy matrix. A kinetic analysis of the cure mechanism of the epoxy resin associated to the catalytical activity of the graphite based fillers was performed by isothermal DSC measurements. The DSC results showed that the addition of all graphite based fillers greatly increased the enthalpy of epoxy reaction and the reaction rate, confirming the presence of a catalytic activity of graphitic layers on the crosslinking reaction between the epoxy resin components (epoxide oligomer and di-amine). A kinetic modelling analysis, arising from an autocatalyzed reaction mechanism, was finally applied to isothermal DSC data, in order to predict the cure mechanism of the epoxy resin in presence of the graphite based nanofiller.

In the public transport system, hand-touch surfaces such as seats in buses, trains, trams, and airplanes represent a reservoir of bacteria and a potential risk for contamination among passengers. The antimicrobial activity of silver has been known since ancient times. In this work, natural leather commonly used in the public transport system was treated with silver through the in situ photoreduction of a silver solution. The morphology of the coating and the distribution of silver clusters were studied by scanning electron microscopy and by energy dispersive X-ray spectroscopy. The amount of silver on the surface was quantified by thermo-gravimetric analysis. The antibacterial capability of the treated materials was checked against Gram-positive and Gram-negative bacteria. Taber test was conducted on silver treated samples in order to study the durability of the treatment. The morphology of the silver coating and its antibacterial capability were analyzed also after the Taber test.In the public transport system, hand-touch surfaces such as seats in buses, trains, trams, and airplanes represent a reservoir of bacteria and a potential risk for contamination among passengers. The antimicrobial activity of silver has been known since ancient times. In this work, natural leather commonly used in the public transport system was treated with silver through the in situ photoreduction of a silver solution. The morphology of the coating and the distribution of silver clusters were studied by scanning electron microscopy and by energy dispersive X-ray spectroscopy. The amount of silver on the surface was quantified by thermo-gravimetric analysis. The antibacterial capability of the treated materials was checked against Gram-positive and Gram-negative bacteria. Taber test was conducted on silver treated samples in order to study the durability of the treatment. The morphology of the silver coating and its antibacterial capability were analyzed also after the Taber test.

The aim of this work was to develop polyamide-6/ organic-modified montmorillonite (omMMT) nanocomposites for the production of hollow parts by rotational molding. Particular emphasis was placed on the mechanical and flame retardancy properties needed for the fabrication of vessels for flammable liquids. The morphology of the melt compounded nanocomposites, produced by melt compounding, was investigated by X-ray diffraction measurements (WAXD), and Transmission Electron Microscopy (TEM) showed an exfoliated structure. Rheological measurements were used in order to verify whether the viscosity of materials was adequate for rotational molding. While thermomechanical analysis has revealed that neat PA6 and its nanocomposites were not suitable for rotational molding, due to the very low thermal stability of the polymer, the addition of a thermal stabilizer, shifted the onset of degradation to higher temperatures, thus widening the processing window of both PA6 and PA6 nanocomposites. Large-scale vessel prototypes were obtained by rotational molding of thermo-stabilized PA6 and its nanocomposites, and samples extracted from the rotomolded parts were characterized with respect to physical and mechanical properties. It was found that the PA6 nanocomposites exhibited significant improvements at cone calorimeter tests in comparison with neat PA6.

Summary:The aim of this work is the development of composite pipes using renewable resources. The pipes, manufactured by filament winding technology, were obtained using an epoxy resin crosslinked with a cardanol based novolac as matrix and jute fibres as reinforcement. Cardanol is a natural oil extracted from the shell of the cashew (Anacardium occidentaleL.) nut. An amount of natural materials higher than 50% by weight was achieved in the final composites. Tensile and parallel plate compression tests were carried out on the composite pipes.

In this work, a thermoplastic sandwich panel was designed, produced, and tested for use in insulating walls of containers for food transportation. A sandwich construction comprising a poly(ethylene terephthalate) core and polypropylene/glass fiber skins was evaluated as possible replacement of systems consisting of polyurethane foam in combination with unsaturated polyester glass‐reinforced skins that are currently used for the manufacture of these structures. Factors were taken into account to satisfy the simultaneous need of thermal insulation and adequate mechanical properties that are required for the production of large flat panels 100‐mm thick. The influences of different manufacturing processes and skin‐core adhesion on the mechanical properties of this thermoplastic sandwich were investigated and are discussed in the text. © 2010 Wiley Periodicals, Inc. Adv Polym Techn 29:137–145, 2010; View this article online at . DOI 10.1002/adv.20186

The impregnation of a glass woven fabric with an amorphous polyethylene terephthalate copolymer (PET‐g) matrix was investigated using a finite element (FE) model for interbundle and intrabundle flow of the matrix. Micrographs of samples obtained by film stacking of PET‐gto impregnate the glass fabric have confirmed the occurrence of interbundle and intrabundle flow, taking place as separate steps. On the basis of this evidence, two different mechanisms for the fiber impregnation were postulated. The first flow process is associated with a macroscale interbundle impregnation, whereas the second is associated with microscale intrabundle impregnation. Two different FE models were developed to simulate the microscopic and macroscopic flow of the matrix, considering a large number of different random fiber arrangements. Both models could account for the non‐Newtonian rheological behavior of the thermoplastic matrix. The microscale impregnation of fibers was simulated by using randomly spaced and nonoverlapping unidirectional filaments. The effect of the number of filaments and the number of random distributions necessary to achieve an adequate accuracy of the method was assessed. The results obtained from the simulation showed that at low pressures, the polymer melt exhibits Newtonian behavior, which makes it possible to predict the tow permeability by the Darcy law. A more difficult situation arises at high pressures because of the non‐Newtonian behavior of the melt. This requires the introduction of a value for the permeability that is also dependent on the rheological properties of the melt. The same non‐Newtonian behavior of the matrix was observed for macroscale impregnation of bundles. © 2010 Wiley Periodicals, Inc. Adv Polym Techn 29:122–130, 2010; Published online in Wiley InterScience (). DOI 10.1002/adv.20179

In this work nanocomposites based on amorphous poly(ethylene terephthalate) (PETg) were developed using melt intercalation. X-ray analysis performed on the PETg nanocomposites showed that intercalation and exfoliation took place during static mixing. The water vapor permeability of PETg nanocomposites was correlated to the volume fraction of the impermeable inorganic part of the omMMT.

In this work polyurethane (PU) matrix nanocomposite, obtained using an organically modified montmorillonite (OMM), was synthesized and characterized. An amount of organoclay ranging from 2% up to 6% by volume was added to the polyol component of the resin before mixing with isocyanate. The microstructure of the composites was investigated by X‐ray diffraction. The glass transition temperature (Tg) of PU nanocomposites, measured using differential scanning calorimeter, increases with increasing the volume fraction of OMM. On the other hand, the heat capacity increment, ΔCp, decreases from that the unfilled PU to that of the sample with 5.7% vol of OMM. Therefore a corresponding increase of the rigid amorphous fraction of PU nanocomposites with nanoclay was observed. Finally, the definition of molecular cooperativity was discussed for this system and the characteristic length of the cooperative region was determined, using the approach proposed by Donth.

The aim of the present work is the development of a method for structural reinforcement of beams obtained by in‐mold extrusion of plastics from solid urban waste. The beams obtained by in‐mold extrusion are commonly used for outdoor furniture and structures. The material used for such applications is mainly composed of low‐density polyethylene derived from bags and films, with small amounts of high density polyethylene and polypropylene, as well as traces of polyethylene terephthalate. This material is usually referred to as “plastic lumber.” Plastic lumber products have a low stiffness, which results in high deflections under flexural loads, particularly under creep loading. In this study, reinforcing rods of high aspect ratio were incorporated into plastic lumber beams in specific positions with respect to the cross section of the beam. The reinforcement of the plastic lumber beams with fine rods is introduced in the typical intrusion process used for the production of unreinforced beams. Glass fiber reinforced pultruded rods were chosen for this purpose from a preliminary evaluation of different materials. Different diameter glass fiber reinforced pultruded rods, including surface‐abraded systems to increase the roughness, were used for the reinforcement of plastic lumber beams. The reinforced beams were tested in terms of flexural stiffness, creep resistance, and pullout resistance of the embedded rods. The results obtained from the mechanical tests showed a significant enhancement of flexural stiffness and creep resistance behavior. The performance at higher stress levels was shown to be significantly dependent on the interfacial adhesion between rods and polymer matrix. © 2009 Wiley Periodicals, Inc. Adv Polym Techn 27:133–142, 2008; Published online in Wiley InterScience (). DOI 10.1002/adv.20131

The propagation of low‐intensity ultrasound in polymers, acting as a high‐frequency dynamic mechanical deformation, can be successfully used to monitor changes in the modulus of polymers associated with glass transition, crystallization, cross‐linking, and other chemical and physical phenomena related to changes in the viscoelastic behavior, such as gelation phenomena. The velocity of sound is related to the polymer storage modulus and density, whereas the absorption of ultrasonic waves is related to the energy dissipation in the material and, therefore, to the loss modulus. Accordingly, ultrasonic measurements have been used by several authors to monitor the evolution of the viscoelastic moduli of polymers as a function of time or temperature and, recently, become a characterization technique of its own right, generally known as ultrasonic dynamic mechanical analysis (UDMA). Often the technique is used in conjunction with rheological methods as a means of providing a better insight into the viscoelastic behavior of polymer systems. As yet UDMA is underutilized primarily because of the low operating temperatures (usually below 100○C) of commercially available ultrasonic transducers, and also due to the requirement of a coupling medium to ensure an efficient energy transfer mechanism between the transducer and the test material. Despite these limitations, this paper shows that the use of ultrasonics is potentially a powerful method for the characterization of polymers, particularly as a tool for online monitoring of events occurring during polymer processing and in the manufacture of polymer matrix composites. The aim of this paper is to review the progress made in recent years, highlighting the potential and reliability of UDMA for monitoring physical transitions in polymers such as glass transition, melting, crystallization, as well as physical changes taking place during curing of thermosetting resins. © 2009 Wiley Periodicals, Inc. Adv Polym Techn 27:63–73, 2008; Published online in Wiley InterScience (). DOI 10.1002/adv.20124

In this preliminary work, a new process is examined for manufacturing hollow parts from continuous fiber‐reinforced thermoplastic polymer. The new process combines the basic idea of bag forming (or bladder‐assisted forming) with the rotation of the mold for the processing of thermoplastic matrix composites. A pressurized membrane is used to compact the composite on the inner wall of a mold, which is placed inside a forced convection oven. The mold is removed from the oven for the cooling stage. The process was initially developed by using a thermoplastic pre‐preg obtained using yarns of commingled E‐glass fibers with isotactic polypropylene (iPP). A preliminary characterization of the thermoplastic composite showed that the material can be consolidated with pressures as low as 0.01 MPa, which is readily achievable with the process of this study. The design of the mold and membrane was carried out on the basis of both structural analysis of the aluminum shell and thermal analysis of the mold. The mold thickness is of great importance with respect to both the maximum pressure allowed in the process and the overall cycle time. Molding was performed on stacks of three and six layers of yarn, varying the applied pressure between 0.01 and 0.05 MPa and maximum temperature of the internal air between 185°C and 215°C. The composite shells obtained under different processing conditions were characterized in terms of physical and mechanical properties. Mechanical properties comparable with those obtained by compression molding and vacuum bagging were obtained. The maximum values obtained are 12.1 GPa and 290 MPa for the flexural modulus and the flexural strength, respectively. Furthermore, the results obtained show that mechanical properties improve with increasing the pressure during the cycle and with the maximum temperature used in the process. © 2007 Wiley Periodicals, Inc. Adv Polym Techn 26:21–32, 2007; Published online in Wiley InterScience (). DOI 10.1002/adv.20085

Air‐coupled ultrasound in one‐side transmission mode has been applied to monitor the curing process of an unsaturated polyester resin, commonly used as a matrix in glass reinforced composites. The evolution of the resin mechanical properties during cure has been measured from the variation of longitudinal velocity. The technique has demonstrated to be a very powerful tool for detecting the structural changes occurring at gelation and vitrification. The no‐contact ultrasonic results have been compared with those obtained using conventional contact ultrasonic measurements, characterized by direct coupling between the transducer and the resin, and with the rheological measurements. The good agreement among the results of the different techniques demonstrates the reliability of air‐coupled ultrasound in monitoring the changes of viscoelastic properties occurring during the cure of thermosetting polymers. A further advantage of the proposed one‐side ultrasonic technique is the absence of physical contact between the transducers and the sample, which is relevant during composite manufacturing, where probe contact could adversely affect the part quality or access from both sides is not practicable. No‐contact ultrasonic cure monitoring is suitable for both stationary and moving liquid or solid samples in several process conditions such as moulding, filament winding, etc., opening the way to new applications of ultrasound in the composite industry.

Advanced braking devices can represent a promising application for ceramic matrix composites (CMC) with functional and structural properties. If the actual advanced braking materials could be at least partially replaced by CMCs, it might become the first consumer market for these materials. CMC containing three main phases, silicon carbide, graphite and carbon fibers were prepared. A systematic analysis of the processing-structure-properties relationship of the composite is carried out. In particular, silicon carbide provides the necessary hardness, whereas graphite is used for its lubricating properties, and carbon fibers are used as reinforcement. The samples, prepared using a reactive bonding technique, exhibited adequate mechanical properties, high resistance to thermal shocks and good stability after many thermal cycles. Morphological and structural investigations have been performed to optimize the content of each component. Preliminary tribological investigations are presented.

Advanced braking devices can represent a promising application for ceramic matrix composites (CMC) with functional and structural properties. If the actual advanced braking materials could be at least partially replaced by CMCs, it might become the first consumer market for these materials. CMC containing three main phases, silicon carbide, graphite and carbon fibers were prepared. A systematic analysis of the processing-structure-properties relationship of the composite is carried out. In particular, silicon carbide provides the necessary hardness, whereas graphite is used for its lubricating properties, and carbon fibers are used as reinforcement. The samples, prepared using a reactive bonding technique, exhibited adequate mechanical properties, high resistance to thermal shocks and good stability after many thermal cycles. Morphological and structural investigations have been performed to optimize the content of each component. Preliminary tribological investigations are presented.

A number of over‐the‐counter slimming products are currently available on the market. However, there is no scientific consensus over their effectiveness in promoting and sustaining weight loss. The need to develop an alternative dietary supplement for the treatment of obesity and overweight makes attractive a polyelectrolyte cellulose‐based hydrogel, crosslinked through a water soluble carbodiimide, as a potential bulking agent or stomach filler for hypocaloric diets. The hydrogel is envisaged to be administered orally to absorb water in the stomach, thus swelling and giving a sense of fullness, and to be finally expelled by fecal way. To this purpose, a preliminary assessment of hydrogel swelling capacity in distilled water has been performed, and the biocompatibility of the material with respect to intestinal tissues has been evaluated in vitro. The direct contact with the intestinal mucosa in vivo has been simulated by contacting the hydrogel with the jejunum tract of rat intestine, and the capacity of the material to maintain the epithelial barrier integrity has been monitored by means of transepithelial electric resistance measurements and lactate dehydrogenase release assay. The reported results evidence that the hydrogel is well tolerated by the intestinal tissue during the expected time of contact in vivo. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 1524–1530, 2006

Epoxy microspheres, with average diameters in the order of 4–5 μm, were first produced as insoluble gel resulting from the reactions of a bisphenolic epoxy resin with an aromatic hardener in solution. They were then used as reactive flow modifiers and toughening agents for bisphenolic epoxy resins with same chemical composition. Thermal analysis, rheological measurements, and impact tests were performed to assess their ability to modify the viscosity of the uncured resin and to determine the effects on the cured resins with respect to the glass transition temperature and impact strength. Two similar epoxy systems modified with the addition of different amounts of microspheres preserve the glass transition temperature of the cured unmodified epoxy. The addition of microspheres is responsible for secondary transition. The addition of a small fraction of microspheres does not affect the reactivity of the epoxy resin, while the inclusion of a higher content leads to a noticeable reduction in the gel time of the epoxy systems, indicating that microspheres are not inert fillers. Finally, a limited enhancement of the toughness of the epoxy resin was observed, as a consequence of strong interactions between the matrix and the microspheres. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 748–757, 2006

Chloroform vapor sorption in semicrystalline syndiotactic polystyrene with a nanoporous crystalline form has been investigated by simultaneous gravimetric and calorimetric analysis to gather information on the sorption process and associated heat of sorption. At the investigated pressures of chloroform vapor, the sorption process is dominated by exothermic adsorption of penetrating molecules in the nanocavities of the crystalline phase. The mass uptake kinetics has been compared with the kinetics of evolution of heat of sorption measured simultaneously. The integral heat of sorption evaluated calorimetrically has been compared to the corresponding value calculated by elaborating gravimetric sorption isotherms at several temperatures evaluated independently through gravimetric sorption experiments. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 1675–1681, 2005

Abstract The aim of this work is to investigate the effects of different plasma treatments on ePTFE abdominal prostheses with the final goal of obtaining a new prosthesis, made of a single strand of ePTFE, with clearly differentiated adhesion properties on the two sides, which should be able to promote tissue ingrowth on one side and prevent post surgical visceral adhesions on the other.

Ultrasonic wave propagation, dynamic mechanical analysis, and dielectric analysis were used to monitor relaxation phenomena during the nonisothermal postcure of unsaturated polyester networks. The measurements covered 6 decades of frequency. As a result, the residual reactive groups, immobilized in the glassy state by vitrification during an isothermal cure step, gained molecular mobility, which promoted the formation of additional crosslinks. After the postcure, the reaction was complete, and the maximum achievable glass‐transition temperature was reached. Moreover, the frequency and temperature dependence of the two relaxations, one related to the glass‐transition temperature of the partially cured sample and the other to the glass transition of the fully cured sample, was evaluated. The Williams–Landel–Ferry equation was used to model the frequency dependence of the main α‐relaxation data obtained with the different techniques. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 43: 596–602, 2005

The ageing of non-expanded wheat starch extrudates containing 37% and 51% water on a dry solids basis (d.s.b.) at 25°C was studied using Differential Scanning Calorimetry (DSC), Wide Angle X-ray Diffraction (XRD), proton Nuclear Magnetic Resonance (NMR) relaxometry and Dynamic Mechanical Thermal Analysis (DMTA). The retrogradation rate increased with water content (∼0.02 h−1 at 37% water (d.s.b.) compared to ∼0.06 h−1 at 51%). While a good correlation was found between the DSC, XRD and NMR data, the kinetics of retrogradation measured by DMTA was delayed. The findings were interpreted in terms of the different molecular processes probed by the different techniques. In addition to the kinetics, information on the physical structure of the partially crystalline retrograded materials were obtained. DSC suggested a broad bimodal melting behaviour, which was attributed to the melting of the crystalline structure followed by the dissociation of the double helices. XRD suggested that at both water contents, the recrystallisation of amylopectin led principally to the A-polymorph. DMTA suggested a significant interaction between the amorphous and crystalline phases, with a requirement of a minimum relative crystallinity index of ∼0.8 (e.g. ∼80% of the crystallinity index of the fully retrograded material), before any increase in the elastic modulus (at 25°C) was measured.

Abstract The power radiated by a surface influences the energy transfer processes following a T4 slope. It is therefore clear that, at high temperature, the study and control of spectral emissivity of materials play a key role in many important technologies: re-entry-vehicle thermal protection shields, high temperature radiators, selective emitters in thermophotovoltaic generators, etc. We have developed a class of thick porous garnet coatings that may raise or lower the spectral emissivity of thermostructural materials in the VIS, NIR, and IR regions. The porosity of the coatings nearly cancels any emission contribution from the underlying materials due to the scattering in the inhomogeneous system: pore/high refraction garnet. The yttrium aluminum garnet polycrystals vary their emissivity as a function of the doping rare earth elements they contain. We achieved an emission control capability in the range 700–3000 nm. Porous coatings have been prepared from ceramic slips containing a reactive colloidal phase and rare earth garnet powders prepared by drying and calcining mixed oxide aqueous gels. Garnet coatings containing Er, Yb, and Tm were prepared with thickness ranging between 50 and 400 microns. The coatings have been investigated by morphological and microstructural studies. A dedicated experimental set up has been developed to measure the spectral emissivity up to 1700 K under different heating conditions.

Summary: The curing process of a commercial vinyl ester (VE) resin was characterized by calorimetric and spectroscopic techniques. A phenomenological kinetic model, experienced in previous studies, was employed to describe the proceeding of curing reactions. The model is able to describe the behavior of the processing variables, i.e. rate and degree of the reaction, during the curing of the resin under different conditions (heating rates). The effect of diffusion control phenomena on the reaction kinetics, associated with the evolution of the glass transition temperature as a function of the degree of polymerization and cross-linking, was taken into account in the formulation of the kinetic model. A simpler model was proposed and verified for a liquid crystalline vinyl ester resin, synthesized by the authors. The model, in particular, did not take into account the effects of vitrification. The kinetic parameters were again evaluated by processing the calorimetric data. The kinetic study of the liquid crystalline monomer is performed after isotropization and therefore, the acceleration effect, associated with the cure in liquid crystalline phase is not taken into account for the kinetic analysis. Also in this case, the comparison between theoretical and experimental data was very satisfying.Experimental (full line) and predicted data (dotted line) of degree of reaction vs. time for the vinyl ester resin.

Curing reactions of photoactivated epoxy resins are assuming an increasing relevance in many industrial applications, such as coatings, printing, and adhesives. Besides these processes, stereolithography (SL) makes use of photoactivated resins in a laser-induced polymerization for 3D building. The kinetic behavior of photocuring is a key point for full comprehension of the cure conditions occurring in the small zone irradiated by the laser beam during the building process. Furthermore, the kinetic analysis is very important to determine the cure time needed for part building in a stereolithographic equipment. The mechanisms involved in a cationic photopolymerization are complex compared with radical photopolymerization. In this paper the photoinitiated polymerization of a commercially available epoxy-based resin for stereolithography (SL5170) was studied by means of differential scanning calorimetry (DSC) and Fourier transform infrared spectroscopy (FTIR). Substantial information about the SL5170 chemical composition and curing mechanism was determined through FTIR analysis. The polymerization rate and the maximum degree of reaction were determined directly from experimental DSC curves. Kinetic characterization of epoxy photopolymerization was carried out as a function of the temperature and irradiation intensity and experimental results were compared with an original mathematical model. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 3484–3491, 2004

The quality of rotational molded products is strongly affected by the sintering behavior of the powders used in the process. In turn, for a given material, the sintering behavior of polymer powders is dependent on the size and the shape of particles obtained in the milling apparatus. The quality of powders for rotational molding is usually determined by means of size distribution, dry flow, and bulk density tests. However, these tests do not provide insight into the relationship between the shape of powders, the milling conditions, and the sintering behavior during the rotational molding cycle. Nevertheless, the application of mathematical tools to powder analysis can significantly improve the efficiency of the grinding process, looking not only at the size but also at the shape of the powder. This can in turn result in a higher reliability of rotational molding and in better performances of the products obtained in processes dominated by the sintering behavior of polymer powders. In this work the grinding process of recycled high-density polyethylene was analyzed using a quantitative approach to the shape and size of the powders. In particular, shape factors, capable of characterizing powders obtained in different milling conditions, were studied. Finally, the influence of the powders' shape and size on sintering behavior was studied by thermomechanical analysis. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 449–460, 2004

The aim of this work is to obtain a chemically cross-linked hydrogel from hyaluronic acid and cellulose derivatives that exhibits sensitivity to variation of the composition of the external absorbing medium and an equilibrium sorption capacity higher than a common hyaluronic acid-based hydrogel, in view of its potential use in prevention of postsurgical soft tissue adhesion. This has been achieved by chemical stabilization of hyaluronic acid (HA) and cellulose derivatives, hydroxyethylcellulose (HEC) and carboxymethylcellulose (CMCNa) through the difunctional cross-linker divinyl sulfone. Significant increase in sorption capacity, both in water and in water solutions at different ionic strength, has been observed for these samples in comparison with hydrogels obtained through chemical stabilization of hyaluronic acid. Moreover, different dehydration procedures adopted for the xerogel synthesis have been used, which resulted in a modulation of the equilibrium sorption capacity. Hyaluronic acid stability has been confirmed by means of NMR analysis.

A fire retardant phosphorous-containing bisphenol compound, bis(3-diethyl phosphono-4-hydroxyphenyl)-sulfide (DPHS), has been inserted in an epoxy network. In particular, a chain extension procedure has been used to incorporate DPHS into a standard bisphenol epoxy resin. Different amine catalysts have been tested to promote the reaction of DPHS with the epoxy oligomer. The cure kinetics of this chain-extended oligomer, using an aliphatic amine (triethylene-tetraamine, TETA) as hardener, has been studied with the aid of differential scanning calorimetry and compared with that of the standard stoichiometric epoxy/TETA formulation. For each formulation the activation energy of the curing reactions has been evaluated by the Kissinger method. The results of thermogravimetric and flammability tests indicate that DPHS promoted the formation of a char, leading to an improved fire resistance. Finally, a comparison of the thermal and mechanical properties of the standard stoichiometric formulation relative to those of the epoxy modified with DPHS, and cured with TETA, showed only marginal changes in the physical and mechanical properties. © 2003 Wiley Periodicals, Inc. Adv Polym Techn 22: 329–342, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/adv.10060

In rotational molding, polymer powders are subjected to heating, melting, cooling, and subsequent solidification in biaxially rotating molds. Heat transfer phenomena during rotational molding are significantly affected by the presence of endothermic and exothermic transitions. In this paper instead of using the traditional moving interface method, a new approach is presented which is applicable to semicrystalline materials like linear low-density polyethylene. Melting is described by a statistical model and crystallization by a kinetic model. The model parameters are determined from differential scanning calorimetry measurements. The one-dimensional unsteady heat conduction equation is solved by a finite difference method. The numerical predictions are in good agreement with experimental data. The overall heat transfer model can be used for process optimization purposes. © 2003 Wiley Periodicals, Inc. Adv Polym Techn 22: 271–279, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/adv.10055

A fire retardant phosphorous‐containing bisphenol compound, bis(3‐diethyl phosphono‐4‐hydroxyphenyl)‐sulfide (DPHS), has been inserted in an epoxy network. In particular, a chain extension procedure has been used to incorporate DPHS into a standard bisphenol epoxy resin. Different amine catalysts have been tested to promote the reaction of DPHS with the epoxy oligomer. The cure kinetics of this chain‐extended oligomer, using an aliphatic amine (triethylene‐tetraamine, TETA) as hardener, has been studied with the aid of differential scanning calorimetry and compared with that of the standard stoichiometric epoxy/TETA formulation. For each formulation the activation energy of the curing reactions has been evaluated by the Kissinger method. The results of thermogravimetric and flammability tests indicate that DPHS promoted the formation of a char, leading to an improved fire resistance. Finally, a comparison of the thermal and mechanical properties of the standard stoichiometric formulation relative to those of the epoxy modified with DPHS, and cured with TETA, showed only marginal changes in the physical and mechanical properties. © 2003 Wiley Periodicals, Inc. Adv Polym Techn 22: 329–342, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/adv.10060

In rotational molding, polymer powders are subjected to heating, melting, cooling, and subsequent solidification in biaxially rotating molds. Heat transfer phenomena during rotational molding are significantly affected by the presence of endothermic and exothermic transitions. In this paper instead of using the traditional moving interface method, a new approach is presented which is applicable to semicrystalline materials like linear low‐density polyethylene. Melting is described by a statistical model and crystallization by a kinetic model. The model parameters are determined from differential scanning calorimetry measurements. The one‐dimensional unsteady heat conduction equation is solved by a finite difference method. The numerical predictions are in good agreement with experimental data. The overall heat transfer model can be used for process optimization purposes. © 2003 Wiley Periodicals, Inc. Adv Polym Techn 22: 271–279, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/adv.10055

The possibility to modulate cellulose-based hydrogel sorption properties through the insertion of molecular spacers between the crosslinks was investigated. Starting polymers were the sodium salt of carboxymethyl cellulose, a polyelectrolyte cellulose derivative, and hydroxyethyl cellulose, a nonpolyelectrolyte derivative. Poly(ethylene glycol) with various molecular weights was linked by its free ends at two divinyl sulfone (DVS) crosslinker molecules, to increase the average distance between two crosslinking sites and thus to act as a spacer. Both the effect of the concentration and the molecular weight of the spacer on the hydrogel final sorption properties in water and water solutions were investigated. The presence of the spacer allowed us also to perform hydrogel synthesis with higher concentrations of cellulose in the reactive mixture, and the effect of the polymer concentration in the batch was analyzed. Hydrogels obtained in the presence of spacers displayed significantly higher equilibrium sorption properties than those of the ones obtained without spacers. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 168–174, 2003

Three different techniques have been applied to the evaluation of the degree of cross‐linking of superabsorbent cellulose‐based hydrogels obtained from water solutions of carboxymethylcellulose sodium salt (CMCNa) and hydroxyethylcellulose (HEC), chemically cross‐linked with divinyl sulfone. These polyelectrolyte hydrogels are biodegradable and have the same sorption capacity as acrylate‐based superabsorbents on the market. A 13C solid state NMR analysis was carried out on dry samples of hydrogel to obtain the degree of cross‐linking, an important parameter that affects the swelling and mechanical properties of a hydrogel. Dynamic mechanical analysis was performed during the hydrogel cross‐linking using a parallel plate rheometer under oscillatory deformations in order to monitor the evolution of the hydrogel viscoelastic properties during the synthesis. The value of |G*| and the slope of the stress‐deformation ratio plots from uniaxial compression tests were used to evaluate the elastically effective degree of cross‐linking according to classical rubber elasticity theory. Moreover, a dynamic mechanical analysis was carried out on cross‐linked hydrogels at different degrees of swelling in order to investigate the influence of the swelling on the mechanical properties and the application of rubber elasticity theory to swollen hydrogels.