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AbstractNon-woven hybrid meshes based on poly(l-lactide-co-d,l-lactide) (dl-PLA) and β-tricalcium phosphate (β-TCP) were fabricated and comprehensively characterized. Stock suspensions of β-TCP powder in dl-PLA acetone solutions were used for the electrospinning process. Structure, morphology and thermal properties of the electrospun samples were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The electrospun hybrid materials show a micro-composite structure, and a morphology characterized by a three-dimensional porous fibrous mesh with randomly distributed fibers possessing average fiber diameters between 680 and 970 nm, uniform thickness along the fibers and beads structure only for higher β-TCP concentration electrospun samples. Both pure PLA and hybrid non-woven meshes exhibit a good thermal stability and a continuous degradation in simulated body fluid medium. A live/dead staining viability assay using MC3T3-E1 preosteoblasts reveals the excellent cytocompatibility of the fabricated non-wovens. Enhanced alkaline phosphatase (AP) activity of MC3T3-E1 cells during culture on the dl-PLA and the composite non-woven meshes demonstrates their potential for applications in hard tissue repair.

This review treats the recent patents and related literature, mainly from the Authors laboratories, on biomedical and food packaging applications of nano-composites constituted of biodegradable polymers filled with micro or nano crystals of organically modified Layered Double Hydroxides of Hydrotalcite type. After a brief outline of the chemical and structural aspects of Hydrotalcite-like compounds (HTlc) and of their manipulation via intercalation of functional molecular anions to obtain materials for numerous, sometime unexpected applications, the review approaches the theme in three separated parts. Part 1 deals with the synthetic method used to prepare the pristine Mg-Al and Zn-Al HTlc and with the procedures of their functionalization with anti-inflammatory (diclofenac), antibacterial (chloramphenicol hemisuccinate), antifibrinolytic (tranexamic acid) drugs and with benzoates with antimicrobial activity. Procedures used to form (nano) composites of polycaprolactone, used as an example of biodegradable polymer, and functionalized HTlc are also reported. Part 2 discusses a patent and related papers on the preparation and biomedical use of a controlled delivery system of the above mentioned pharmacologically active substances. After an introduction dealing with the recent progress in the field of local drug delivery systems, the chemical and structural aspects of the patented system constituted of a biodegradable polymer and HTlc loaded with the active substances will be presented together with an extensive discussion of the drug release in physiological medium. Part 3 deals with a recent patent and related papers on chemical, structural and release property of antimicrobial species of polymeric films containing antimicrobial loaded HTlc able to act as active packaging for food products prolonging their shelf life.

The increased demand for high‐quality multifunctional materials in the aeronautic industry requires the formulation and preparation of advanced nanostructured composites with superior characteristics. In particular, epoxy‐based polymers, exhibiting excellent mechanical properties for structural stability, filled with carbon nanotubes (CNTs: single, double, and multiwalled—SW, DW, and MW), characterized by remarkable mechanical and electrical properties, allow us to manufacture a very versatile class of composites for structural applications in automotive, aeronautics, industry, electronics, etc. Many aspects concerning the optimization of such composite systems are still to be clarified. In this paper, the physical properties of samples based on the epoxy resin with the same weight percentage (0.5%) of different CNTs have been studied. The physical behavior of the nanocomposites resulted to be dependent on the type and on the chemical functionalization of the nanoinclusions. The elastic modulus and the electrical conductivity of composites based on unfunctionalized CNT are higher than those obtained for the functionalized systems. Moreover, the maximum electrical conductivity achieved for the composite based on unfunctionalized MWCNT is not far from the target required for aeronautic applications. The contrasting results obtained for the different physical properties enlighten the difficulty in choosing one of the CNT types for the realization of multifunctional materials. © 2012 Wiley Periodicals, Inc. Adv Polym Techn 31: 205–218, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/adv.21284

In this paper, we report the study and characterization of a multifunctional autonomically healing composite containing solid particles of Grubbs’ first generation catalyst and poly(urea-formaldehyde) microcapsules filled with liquid DCPD. This system, already reported in literature, in some respects shows great potential for epoxy structural composites: however, other aspects have to be explored in order to put to use in advanced applications. Here, we have determined the curing process to obtain the best mechanical performance without deactivating the self-repair activity of the material. It has been found that, for the same curing cycle, the presence of catalyst powder causes a slight decrease in the elastic modulus value with respect to the epoxy matrix. A large recovery in this performance is gained for the self-healing specimen, proving that the microcapsules contribute to improve the mechanical characteristics of the self-healing sample.

Benzoate (Bz), 2,4-dichlorobenzoate (BzDC), and p- and o-hydroxybenzoate (p- and o-BzOH) anions with antimicrobial activity have been intercalated into [Zn0.65Al0.35(OH)2](NO3)0.35·0.6H2O, layered double hydroxide (LDH), via anion-exchange reactions. The composition of the obtained intercalation compounds, determined by chemical, thermogravimetric, and ion chromatographic analyses, indicates that benzoate and benzoate derivative anions replace the nitrate counteranions, almost completely. Information on the interactions of the intercalated anions with the inorganic layer have been obtained from Fourier transform IR absorption spectroscopy and powder X-ray diffraction of the samples. It has been found that both the nature and the position of the aromatic ring substituents affect the value of the basal distance and the host-guest hydrogen bond network. Knowledge of the chemical composition, basal distance, and van der Waals dimensions of the guests has finally allowed the proposal of structural models of the intercalation compounds that have been used as fillers of poly(caprolactone), a biodegradable polymer. Films of polymeric composites were obtained by hot-pressing the powders of polymer and filler previously milled by a high-energy ball milling procedure. X-ray diffraction analysis and optical and scanning electron microscopy of the composites indicate that the LDH samples containing BzDC anions are delaminated into the polymeric matrix, whereas those containing p-BzOH anions maintain for the most part the crystal packing and give rise to microcomposites. Intermediate behavior was found for LDH modified with Bz and o-BzOH anions because exfoliated and partly intercalated composites were obtained. Preliminary antimicrobial tests indicate that the composites are able to inhibit the Saccharomyces cerevisiaegrowth of 40% in comparison with the growth in a pure culture medium. The composites can be studied as the model for “active packaging” systems because of the antimicrobial properties of the anions anchored to the LDH layer.

With differential scanning calorimetry, we have demonstrated a peculiar behavior under equilibrium conditions of neat poly(ɛ‐caprolactone) and its organophilic montmorillonite nanocomposites. In particular, in the determination of the equilibrium melting temperature by the extrapolation of the data of the melting temperature (Tm) versus the crystallization temperature (Tc), a bimodal trend has been observed. At the lower Tc's, the data of Tm follow a constant trend, whereas at the higher ones, the usual increasing trend has been obtained. Morphological observations by atomic force microscopy (AFM) have provided evidence of two different crystalline morphologies for the lower and higher Tc ranges. Moreover, AFM has shown that the thermal treatments strongly influence the clay dispersion in the polymer matrix. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 22–32, 2006

Samples of polyurethane nanocomposites were synthesized using diphenylmethane diisocyanate, poly(ɛ‐caprolactone) diol, di(ethylene glycol), and a clay functionalized by hydroxyl groups. The inorganic content in the hybrids was 2 wt %, 4 wt %, and 8 wt %. The X‐ray analysis showed that exfoliation occurred for clay content equal to 2% (w/w), whereas for higher contents, the inorganic phase rearranges in an intercalated structure. FTIR analysis suggested that the degree of hydrogen bonding in the hard segments was greatly reduced because of the amount of silicate layers and their dispersion. The dynamic‐mechanical analysis showed that the presence of clay lamellae extends very much the temperature range before the hard domain transition, causing the loss of mechanical consistency of the samples. It is less than 100 °C for the pure polymer, and increases up to 200 °C for the nanocomposites. The permeability of water vapor decreases linearly with inorganic content up to 4% of inorganic phase, and levels off at higher concentrations. The permeability behavior, at low activities, is largely dominated by the diffusion phenomenon. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 43: 2454–2467, 2005

12‐Hydroxydodecanoate (HD) anions were intercalated, via an ion‐exchange procedure, onto a Mg/Al hydrotalcite‐like compound with the formula [Mg0.65Al0.35(OH)2](NO3)0.35·0.56H2O. The obtained intercalate, characterized by chemical and thermal analyses, X‐ray powder diffraction, and Fourier transform infrared spectroscopy, had the formula [Mg0.65Al0.35(OH)2](NO3)0.08(HD)0.28·0.56H2O and an interlayer distance of 2.27 nm. Structural considerations indicated that the charge‐balancing HO&bond;(CH2)11&bond;COO− anions were accommodated in the interlayer region as a monofilm of partially interdigitated alkyl chains in a trans planar conformation and bearing the alcoholic group. The organically modified hydrotalcite was used to prepare novel composites based on poly(ε‐caprolactone) (PCL) with different procedures: (1) solvent casting, (2) ring‐opening polymerization of ε‐caprolactone, and (3) blending of precursors consisting of a PCL intercalated oligomer with a high‐molecular‐weight PCL. Microcomposites were obtained by the solvent casting of a mixture of a high‐molecular‐weight PCL and the modified hydrotalcite. The ring‐opening polymerization of ε‐caprolactone initiated by the &bond;OH groups of the alkyl chains intercalated in the hydrotalcite led to hybrid materials in which a low‐molecular‐weight PCL was in part intercalated into the modified hydrotalcite. Nanocomposites containing exfoliated hydrotalcite were obtained through the mixing, in different weight ratios, of hybrids consisting of PCL oligomers and modified hydrotalcite with a commercial high‐molecular‐weight PCL. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 2281–2290, 2005

Summary:Nanocomposite materials were obtained by blending multi‐wall carbon nanotubes (CN), obtained by acetylene catalytic chemical vapour deposition (CVD) on Co/Fe‐modified NaY zeolite, with syndiotactic poly(propylene) (sPP). The nanotubes, well dispersed in the polymer matrix, favour the crystallization of the sPP helical chains and significantly improve the sPP thermal stability either in nitrogen or in air. The morphology of the sPP affects the behaviour of the sPP degradation in air.

In the last few years much progress has been made in the development of hybrid polymer–inorganic filler nanocomposites. Nevertheless, many questions remain. The comprehension of the structure and the interactions at the polymer–nanofiller interface are crucial to foresee and control the properties of nanocomposites. Because of the high surface ratio of the inorganic nanofiller, the interface is expected to have a prevailing role in determining the nanocomposite properties. In this study we use X‐ray photoelectron spectroscopy (XPS) as a tool for the surface characterization of an organophilic montmorillonite/poly(ɛ‐caprolactone) exfoliated nanocomposite. The XPS core levels of the nanocomposite have been compared with those obtained from its precursors, and analyzed as reference compounds to evaluate eventual differences attributable to the polymer–nanofiller interfacial interactions. The XPS investigation has allowed us to propose a qualitative model of possible interface interactions between poly(ɛ‐caprolactone) and the organo‐modified montmorillonite. The model is substantiated by Fourier transform infrared spectroscopy (FTIR). © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 3907–3919, 2004

The transformations of the trans‐planar mesophase of syndiotactic polypropylene (sPP) subjected to thermal, mechanical and solvent treatments, were investigated. The unoriented trans‐planar mesophase, obtained by quenching the melt at 0°C, was annealed at 80°C and the thermal transformation was investigated by X‐rays, infrared and dynamic‐mechanical analysis. The presence of the helical form II was recognized in the annealed sample. The oriented trans‐planar mesophase, obtained by drawing at room temperature and releasing the tension, was immersed in liquid dichloromethane for 24 hours. After drying the sample showed the presence of the oriented form II, although it was not possible to exclude a partial transition into form IV. On the basis of the present and literature results we suggested a scheme of the polymorphic transitions of sPP, in which the central role of the trans‐planar mesophase is enlightened.

Poly(ɛ-caprolactone) (PCL) chains grafted onto montmorillonite modified by a mixture of nonfunctional ammonium salts and ammonium-bearing hydroxyl groups were prepared. The clay content was fixed to 3 wt %, whereas the hydroxyl functionality was 25, 50, 75, and 100%, obtaining an intercalated or exfoliated system. The transport properties of water and dichloromethane vapors and the mechanical properties were investigated. The mechanical and dynamic mechanical analyses showed improvement of the nanocomposite elastic modulus in a wide temperature range. Interestingly, for the higher hydroxyl contents (50, 75, and 100%), the decrease of modulus at higher temperature, due to the PCL crystalline melting, did not lead to the loss of mechanical consistence of the samples. Consequently, they revealed a measurable modulus up to 120 °C, a much higher temperature with respect to pure PCL. Water sorption was investigated in the entire activity range, and a lower sorption was observed on increasing the hydroxyl content, up to the sample with 100% hydroxyl content, which turned to be completely impermeable, even in liquid water. The sample with 75% hydroxyl content showed a threshold activity (a = 0.4) below which it was impermeable to water vapor. Also, the diffusion parameters decreased when the hydroxyl content increased, up to the 100% sample, which showed zero diffusion. The diffusion parameters of an organic vapor, dichloromethane, also exhibited a decreasing value on increasing the hydroxyl content in the nanocomposites. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 1466–1475, 2004

The thermal behavior and overall isothermal crystallization kinetics of a series of organophilic modified montmorillonite–poly(ε-caprolactone) nanocomposites were investigated. In general, the thermal behavior was influenced more by the type of dispersion than by the clay content. For nanocomposites in which silicate platelets were predominantly dispersed in the polymer matrix to give exfoliated structures, the thermal properties were improved with respect to those of neat poly(ε-caprolactone), whereas in those cases in which simply intercalated structures were attained, the thermal properties regularly decayed as the clay content increased. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 1321–1332, 2004

The phase behavior and the crystallization kinetics of blends composed of isotactic polypropylene (iPP) and linear low-density polyethylene (LLDPE) were investigated by differential scanning calorimetry. The phase behavior indicates the formation of separate crystals of iPP and LLDPE at each investigated blend composition. The crystallization trace reveals that iPP crystallizes in its normal range of temperatures (i.e., at temperatures higher than that of LLDPE), when its content in the blend is higher than 25% by weight. In the blend whose iPP content is as high as 25%, at least a portion of iPP crystallizes at temperatures lower than that of LLDPE. This behavior has been proposed by Bassett to be attributed to a change in the kind of nucleation from heterogeneous to homogeneous. From the Avrami analysis of the isothermal crystallization of iPP in the presence of molten LLDPE, n values close to 2 are always obtained. According to our previously proposed interpretation of the Avrami coefficient, it can be related to the crystallite fractal dimension, through d = n + 1, which gives values close to 3, according to the spherulitic observed morphology. The kinetics parameter, i.e., the half-time of crystallization, and the kinetic constant k show that a decrease in the overall rate of crystallization of iPP occurs on blending. Optical microscopy photographs, taken during the cooling of the samples from the melt, confirm the above results and show increasingly less resolved spherulite texture on increasing LLDPE content in the blend. The diffusion parameters evaluated for the neat polymers and for the blends in dichloromethane, which give information on the miscibility in the amorphous state, show that the diffusional behavior of the blends is governed by iPP, suggesting a two-phase amorphous state. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 3338–3346, 2003

Three syndiotactic polypropylene samples were crystallized under different conditions in order to obtain different polymorphs. A first sample was crystallized at high temperature, obtaining the helical form I; a second was crystallized from the melt at 0°C for many days obtaining the trans‐planar mesophase; a third sample was obtained by solvent induced crystallization followed by annaeling of the trans‐planar mesophase, leading to a mixture of both the helical forms I and II. In the dynamic‐mechanical analysis the helical form I showed only one peak of tan δ corresponding to the amorphous glass transition. The other polymorphs also showed this transition centered at about the same temperature. Beside the peak corresponding to the Tg, the trans‐planar mesophase was characterized by a peak appearing at 70°C, and the helical form II by a peak at 100°C. These peaks, unambiguously associated to transitions of the different forms, can be considered a distinctive evidence for the polymorphs obtained in different processing conditions.

Isotactic polypropylene nanocomposites were obtained by the melt blending of polypropylene-graft-maleic anhydride and organophilic layered silicate (OLS) consisting of synthetic fluorohectorite modified by cation exchange with protonated octadecylamine. The composition of the inorganic clay was varied between 2.5 and 10 wt %, and films of the composites were obtained via hot-press molding. X-ray analysis showed that nanocomposites in which silicate layers were either delaminated or ordered as in an intercalated structure were obtained. The elastic modulus of the samples was higher than that of the pure polymer over a wide temperature range and increased with increasing inorganic content. The transport properties, sorption and diffusion, were measured for two organic vapors, dichloromethane and n-pentane. For both vapors, the sorption was not very different from that of the pure polymer, whereas the zero-concentration diffusion parameter strongly decreased with increasing OLS content. Therefore, the permeability, that is, the product of sorption and diffusion, decreased for both vapors as a result of the decreased value of the diffusion parameter. The decrease was higher for the less interacting n-pentane. © 2003 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 41: 1798–1805, 2003

Abstract. The solvent induced crystallization phenomenon (SINC) was studied for syndiotactic polypropylene quenched from the melt at 0 °C and kept at this temperature a for long time. In these conditions a mesophase having the chains in trans-planar conformation was formed. The interaction polymer-solvent with liquids having different solubility parameters, derived by both the swelling and the weight uptake, considerably varies among the different liquids, showing a maximum corresponding to carbon tetrachloride (δ=8.6). A smaller maximum was found for chloroform (δ=9.3). These two maxima were attributed to interaction either with the amorphous phase or with the trans-planar mesophase. Infrared analysis showed that all the liquids induce a conformational transition from trans-planar to helix, and only a small residual fraction of chains in trans-planar conformation was detected for the samples immersed in the liquids and vacuum dried for many hours. The X-ray analysis showed that the quenched sample undergoes in the solvents a complex transformation, partially crystallizing into the helical form I and partially into the helical form II. All the liquids induced the same transformation, in spite of very different levels of interaction.

A black colorant alternative to carbon black, for Polyethylene tanks, which avoids the hysteresis of solvent and allows a more friendly recycling process, was studied. Sorption-desorption isotherms where obtained using a model molecule (n-heptane), in order to simulate the contact with the fuel. The material pigmented with the alternative black colorant was put in contact with liquid fuel for six months: after desorption the rheological behaviour was analyzed at 240°C. Films were obtained after contact with fuel, and submitted to dynamic mechanical analysis. The experimental data were compared with the ones obtained from the material utilized by FIAT Company (Italy) for fuel tanks (carbon black pigmented), both virgin and used ones.

Polyethylene (PE) from postuse automotive fuel tanks is considered a valuable material for mechanical recycling, and we assessed its properties, paying particular attention to transport properties and processability. The characterization included the study of the sorption–desorption isotherms, the rheological analysis of the molten materials and their processability. In particular, we obtained, sorption-–desorption isotherms using a model molecule (n-heptane) to simulate contact with the fuel. The measurements were carried out on films of PE blend for tanks and separately on the components of the blend. Rotational rheometry was carried out on scraps from used tanks and on virgin material for comparison. We performed some extrusion tests to evaluate the possibility of mechanical recycling of the postuse materials. In particular, we examined the melt-fracture incoming conditions by making use of a twin-screw extruder with a round die. Stress–strain measurements were carried out on films of virgin and used material, obtained with a press on a laboratory scale to evaluate the change of the mechanical properties of a manufacture obtained by reprocessing a polymer aged in contact with a mixture of liquids. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 347–351, 2002

Four samples of syndiotactic poly(propylene) were synthesized by changing either the polymerization temperature or the catalytic system. Samples with different molecular weights were obtained, ranging between 27 000 and 826 000, whereas the fraction of syndiotactic pentads was found very near in the different samples, ranging between 88 and 91%. The polymer powders were quenched from the melt in an ice-water bath, extracted at room temperature and aged for 1 month. Changes in the structural organization during the ageing time at room temperature were followed by X-rays, transport properties and infrared analysis. The X-ray diffractograms showed that all the fresh samples crystallized in the disordered helical form I, containing also a fraction of chains in trans-planar conformation. The helical crystallinity was found very similar for all the samples, and a small increase of this parameter, not higher than 4–6%, was observed during the ageing time. At variance, the study of sorption of a vapor at low activity indicated the presence of an intermediate phase not crystalline, yet impermeable to the vapors, increasing during the ageing at room temperature. The fraction of the intermediate phase was very high in the lowest molecular weight sample, and decreased on increasing the molecular weight, reaching a constant value for molecular weights higher than 80 000. The analysis of the infrared spectra showed that the helical bands increase during the ageing, indicating that the intermediate phase is composed by very small and disordered helical crystals. The elastic modulus of each sample was measured soon after quenching and during the ageing. It was found a consistent increase of this parameter, not ascribable only to the small increase of crystallinity. The increase of the elastic modulus of all the samples was correlated to the increase of the intermediate phase derived by sorption, and a good dependence on this parameter was found. The absorbance of the helical bands at 810, 868, and 977 cm⁻¹, as a function of the ageing time.

The structural characterization and transport properties of blends of a commercial high molecular weight poly(ε-caprolactone) with different amounts of a montmorillonite-poly(ε-caprolactone) nanocomposite containing 30 wt % clay were studied. Two different vapors were used for the sorption and diffusion analysis—water as a hydrophilic permeant and dichloromethane as anorganic permeant—in the range of vapor activity between 0.2 and 0.8. The blends showed improved mechanical properties in terms of flexibility and drawability as compared with the starting nanocomposites. The permeability (P), calculated as the product of the sorption (S) and the zero-concentration diffusion coefficient (D0), showed a strong dependence on the clay content in the blends. It greatly decreased on increasing the montmorillonite content for both vapors. This behavior was largely dominated by the diffusion parameters. © 2002 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 40: 1118–1124, 2002

A series of montmorillonite-poly(ɛ-caprolactone) nanocomposites were prepared according to a two-stage procedure. In the first step Na-type silicate clay was cation exchanged with protonated 12-aminolauric acid. In the second step ɛ-caprolactone was intercalated in the modified clay and ring-opening polymerized. The clay content was varied regularly from 0 to 44 wt.-%, with exfoliation of the silicate layers being detected by X-ray diffraction in the nanocomposites dispersing up to at least 16 wt.-% clay. Crystallization of poly(ɛ-caprolactone) was not prevented in the nanocomposites, although it proceeded to a lower extent/order than in a homopolymer sample. The transport properties were investigated using water or dichloromethane as vapor permeants. In each case, a dual sorption behavior was observed as a function of the vapor activity because of the occurrence of different sorption mechanisms. The permeability of the nanocomposites to either permeant decreased with increasing clay content. In particular, the permeability behavior to water was largely dominated by the diffusion parameter.

Syndiotactic polypropylene (sPP) was cast‐extruded with a laboratory single screw extruder, obtaining a crystalline and still highly transparent film.

Syndiotactic polypropylene (sPP) was cast-extruded with a laboratory single screw extruder, obtaining a crystalline and still highly transparent film. The structural studies showed that the film crystallized at room temperature in the disordered helical form I, containing a fraction of a mesophase with the chains in trans-planar conformation. X-ray patterns, taken either along the extrusion direction (MD) or along the orthogonal directions (TD and ND), indicated a low orientation of the c axis parallel to the machine direction (MD) and a partial orientation of the a axis along the transverse direction (TD). Mechanical properties performed in either direction showed a very similar behaviour, but a different strain at the breaking point. The mechanical parameters were derived in both directions.

Samples of polyurethane and organically modified montmorillonite (OMont) were prepared, covering a wide range of inorganic composition, up to 40 wt%. They were obtained by a three step process using diphenylmethane diisocyanate, poly(ɛ-caprolactone), di(ethylene glycol) and poly(ɛ-caprolactone)-OMont (NPCL) nanocomposites. The NPCL nanocomposites were used as soft segments for a partial replacement of the di(ethylene glycol) in the hard-segment of the polymeric chains. The X-ray analysis showed that exfoliation occurred for low montmorillonite content, whereas for higher contents the intercalated clay rearranged to a minor extent. The mechanical and dynamic-mechanical analysis showed an improvement of the elastic modulus and yield stress, but a decrease of the stress and strain at breaking on increasing the clay content. Sorption and diffusion were measured for two different vapors, i.e. water vapor as hydrophilic permeant and dichloromethane as hydrophobic one. For both vapors the sorption did not drastically change on increasing the clay content. At variance the zero-concentration diffusion parameter ( D 0 ) strongly decreased on increasing the inorganic content. The permeability, calculated as the product of the sorption ( S ) and the zero-concentration diffusion coefficient ( D 0 ) showed a remarkable decrease up to 20% of clay and a leveling off at higher contents. It was largely dominated by the diffusion parameter.

A syndiotactic poly(propylene) film (sPP), quenched from the melt at 0°C, was drawn at room temperature up to a draw ratio of λ= 6. The fibre was analysed under tension by X‐ray analysis and FTIR spectroscopy, showing the presence of the oriented crystalline form III described by Chatani, with the chains in trans‐planar conformation. Then it was unhooked, undergoing a large shrinkage, and reaching a length corresponding to a draw ratio of λ= 3.8. X‐ray and FTIR analysis showed that in the relaxed fibre, a conformational transition from the trans‐planar to the helical form occurred. The relaxed fibre was again submitted to increasing extensions up to λ= 6, step by step, and the elastic behaviour was analysed through the Mullins' curve and hysteresis cycles. It showed good elastic properties, which appear to be closely correlated to the conformational transition between helical and trans‐planar forms.

•Active coating based on LDH hosting sorbate as antimicrobial was prepared.•PP films were coated with the nano-carrier and antimicrobial activity evaluated.•White bread was packaged at ambient temperature in active packaging and a control.•Bread stored in the active film maintained its characteristics up to 12 days•The process proposed is cheap safe and easily industrially scalable.

In this work we compare calorimetric and X‐ray diffraction experiments realized on annealed sPS in helical γ forms resulting by different treatements: From clathrate δ form and from interaction of amorphous sample with acetone. The experimental results show that the γ form obtained by acetone converts into the more ordered final α” form modification; while the γ form, obtained by thermal treatments of δ form, transforms into the poorly ordered final α' form.

Physical aging in polyethylene terephtalate (PET) has been studied on samples well characterized in terms of aging history and their content of water. This allows us to better understand the role played by water in the complex phenomenology of the physical aging in a hygroscopic material as PET. No appreciable changes in the thermal behavior in the sample aged in water at room temperature for one month were noted, while substantial changes were observed in samples aged in more severe conditions like 50°C under vacuum and 50°C in water for one month. The results are consistent with the formation of small regions in which segments of chains are closely packed.

The crystallization from the glassy state of different samples of isotactic polystyrene (iPS) was investigated with different techniques, such as differential scanning calorimetry, infrared analysis, and polarized optical microscopy. The different samples of iPS were obtained by aging the glassy iPS films at room temperature and at 70°C; the behavior of the aged films was compared with that of a fresh sample, brought to the crystallization temperature as soon as prepared. The temperature of crystallization was 140°C. All the techniques investigated to follow the crystallization phenomenon show that the fresh sample crystallizes much later than the others; the sample aged at 70°C takes the shortest time to crystallize, whereas intermediate behavior is shown by the sample aged at room temperature. This result was correlated with the initial structural organization of the glassy amorphous samples.

Amorphous films of syndiotactic polystyrene were crystallized in dichloromethane, to obtain samples in the clathrate δ form; successively the samples were either annealed at temperatures below the glass transition temperature (Tg) or extracted with acetone. The samples obtained show, in the X-ray analysis, crystalline structures tending toward the “emptied” δ form, free of solvent molecules, as already described for sPS. The study of the transport properties, diffusion and sorption of dichloromethane vapor, shows that the annealed samples are characterized by a slightly lower diffusion coefficient, but much higher sorption at low activity of the vapour. This high sorption is explained by the penetration of solvent molecules both into the amorphous and the “emptied” crystalline phase, producing again the clathrate form at low vapour activity. The high sorption capability makes these samples promising as sorption media to remove traces of polluting chlorinated solvents both in the liquid and in the vapour phase.

Amorphous films of syndiotactic polystyrene were crystallized in dichloromethane, to obtain samples in the clathrate δ form; successively the samples were either annealed at temperatures below the glass transition temperature (Tg) or extracted with acetone. The samples obtained show, in the X-ray analysis, crystalline structures tending toward the “emptied” δ form, free of solvent molecules, as already described for sPS. The study of the transport properties, diffusion and sorption of dichloromethane vapor, shows that the annealed samples are characterized by a slightly lower diffusion coefficient, but much higher sorption at low activity of the vapour. This high sorption is explained by the penetration of solvent molecules both into the amorphous and the “emptied” crystalline phase, producing again the clathrate form at low vapour activity. The high sorption capability makes these samples promising as sorption media to remove traces of polluting chlorinated solvents both in the liquid and in the vapour phase.

Due to a typing error, the name of the second co‐author, Liberata Guadagno, was spelled incorrectly. We would like to apologize for any inconvenience this mistake may have caused!

Due to a typing error, the name of the second co-author, Liberata Guadagno, was spelled incorrectly. We would like to apologize for any inconvenience this mistake may have caused!