We report in this study the synthesis of core-degradable spherical nanoparticles via reverse-sequence polymerization-induced self-assembly (PISA) under aqueous conditions. A hydrophobic poly[(ethylene carbonate)-co-(ethylene oxide)] (PECEO) copolymer sample was utilized to synthesize the PECEO macro chain-transfer agent (PECEO macro-CTA), which was subsequently chain-extended with N,N '-dimethylacrylamide (DMAA) via reversible addition-fragmentation chain transfer (RAFT) polymerization, leading to the formation of stable spherical nanoparticles. In all cases, near-quantitative monomer conversion was achieved, as confirmed by 1H NMR spectroscopy. Dynamic light scattering (DLS) analysis confirmed the formation of spherical nanoparticles with diameters in the 20-30 nm range. The incorporation of carbonate units within the polymer backbone conferred degradability to the nanoparticle, as further demonstrated by size exclusion chromatography (SEC) and 1H NMR analyses when those nanoparticle suspensions were subjected to basic conditions.

The kinetics of polycyclotrimerization of cyanate ester resin (CER), viz. dicyanate ester of bisphenol E (DCBE), was studied by DSC method during its molecular design at ultra-low content (0.1 wt%) of two types of nanofillers: reactive aminopropylisobutyl polyhedral oligomeric silsesquioxane (APIB-POSS) or inert fullerene C-60 having inorganic closed cage structure of nanomolecules. The polycyclotrimerization of DCBE was significantly accelerated in the presence of APIBPOSS, and its nanoparticles were covalently incorporated into the structure of the growing polycyanurate (PCN) matrix to form a hybrid organic-inorganic PCN/APIB-POSS network. Using FTIR, H-1 NMR and C-13 NMR spectroscopy for the DCBE/APIB-POSS (50/50 wt%) reactive blend the chemical interaction between the NH2 groups of APIB-POSS and the -OC equivalent to N groups of DCBE was confirmed even from the beginning of mixing of the components at T approximate to 20 degrees C. In contrast, the distribution of inert C-60 nanoparticles in DCBE slowed down its polycyclotrimerization, but, unexpectedly, this led to the formation of a PCN/C-60 nanocomposite with increased glass transition temperature (T-g) reaching 277 degrees C, which is 24 degrees C higher than the T-g of unfilled PCN. The nanocomposites developed are characterized by high thermal stability (& Tcy;(d5%) > 440 degrees C).

As an abundant byproduct of hydrodesulfurization in petroleum refining processes, elemental sulfur has become a major environmental concern due to its costly disposal and challenging storage. However, the development of synthetic and processing methods to convert elemental sulfur into useful chemicals has not been widely investigated. In this study, we report the development of a novel multicomponent polycondensation (MCP) involving sulfur, diamines, and malonic acid under mild conditions to produce polythioureas. A family of 13 polythioureas with high structural diversity (seven homopolymers and six copolymers) is successfully synthesized from seven commercially available diamines, achieving high yields (up to 96%) and high molar masses (up to 115 900 g/mol). In particular, we report the first ever synthesis of a new biosourced polythiourea from naturally abundant vanillin with good yield upon applying this newly developed MCP.

Building on the development history of the Microbially Induced Calcite Precipitation (MICP) method and recent insights into the organization of liquid and bubbles within pore spaces filled with liquid foam, we hypothesize a potential synergy between MICP and liquid foam for enhancing soil properties. We assess the respiration and calcification capabilities of the bacterium Sporosarcina pasteurii in various foaming solutions formulated with bio-based surfactants. The most promising formulations are then used for in-situ observations of bacteria-induced calcification within foam-embedded 2D granular packings. We observe that maltoside-type AlkylPolyGlucosides with relatively short chains, in particular, enable optimal calcification in less than an hour. In the granular packing, the foam spontaneously creates liquid zones enriched with bacteria at the inter-grain contacts. As a result, instead of being distributed across the entire porous space, calcification is localized in these zones, promoting the formation of solid bridges (CaCO3). This suggests that the foam-based MICP method could represent a relevant variation of the original approach, though this remains to be confirmed at larger scales through mechanical testing on representative soil samples.

A novel method for creating a porous structure in films of heat-resistant polymer composites based on cyanate ester resin (CER) and hexagonal boron nitride (h-BN) was investigated by using neutron irradiation, followed by chemical etching of tracks generated. h-BN (0.1-2.0 wt%) was dispersed in CER using ultrasonic treatment and high-speed stirring and the CER/h-BN composite samples were synthesized in situ by dynamic heating of the mixture to 250 degrees C. Firstly, the effect of h-BN on the kinetics of CER polycyclotrimerization as well as on the composites thermophysical, viscoelastic, and thermal properties, was studied. Unexpectedly, a significant catalytic effect of h-BN on the CER polycyclotrimerization was detected: the higher the h-BN content, the more significant the effect. Secondly, the CER/h-BN composite films were irradiated by neutrons ((1)n). As a result of the well-known nuclear reaction, the B-10 isotope transformed into lithium 7 (Li-7) with formation of alpha-particles (He-4) and gamma-rays. The high-energy alpha-particles formed tracks along their path destroying chemical bonds in the CER/h-BN composites. Porous structures with a multiple pore size distribution were thus generated: an average pore diameter of 7.2-8.5 nm (depending on the initial h-BN content) was determined, due to the etching of tracks formed by alpha-particles, and an average pore diameter of 0.18-1.88 mu m was also measured, due to the removal of destroyed h-BN particles. All CER/h-BN precursors and resulting porous CER films retained high T-g values and thermal stability.

Collagen and gelatin are essential natural biopolymers commonly utilized in biomaterials and tissue engineering because of their excellent physicochemical and biocompatibility properties. They can be used either in combination with other biomacromolecules or particles or even exclusively for the enhancement of bone regeneration or for the development of biomimetic scaffolds. Collagen or gelatin derivatives can be transformed into nanofibrous materials with porous micro- or nanostructures and superior mechanical properties and biocompatibility using electrospinning technology. Specific attention was recently paid to electrospun mats of such biopolymers, due to their high ratio of surface area to volume, as well as their biocompatibility, biodegradability, and low immunogenicity. The fiber mats with submicro- and nanometer scale can replicate the extracellular matrix structure of human tissues and organs, making them highly suitable for use in tissue engineering due to their exceptional bioaffinity. The drawbacks may include rapid degradation and complete dissolution in aqueous media. The use of gelatin/collagen electrospun nanofibers in this form is thus greatly restricted for biomedicine. Therefore, the cross-linking of these fibers is necessary for controlling their aqueous solubility. This led to enhanced biological characteristics of the fibers, rendering them excellent options for various biomedical uses. The objective of this review is to highlight the key research related to the electrospinning of collagen and gelatin, as well as their applications in the biomedical field. The review features a detailed examination of the electrospinning fiber mats, showcasing their varying structures and performances resulting from diverse solvents, electrospinning processes, and cross-linking methods. Judiciously selected examples from literature will be presented to demonstrate major advantages of such biofibers. The current developments and difficulties in this area of research are also being addressed.

This chapter is devoted to the description of the main recent approaches and technical solutions for the creation of polymer micro- and nanofibers engineered by electrospinning precursors of thermosetting polymers. Structure-property relationships have been analyzed for miscellaneous complex systems, including epoxy electrospun micro and nanofibers; submicron carbon nanotube−epoxy nanocomposite filaments, rigid fibers based on functional polynorbornenes with epoxy or carboxylic pendant groups, and core-shell nanofibers with a structure of semi-interpenetrating polymer network (semi-IPN) based on thermoplastic polyamide and thermosetting epoxy resin. The first experimental results for creating electrospun nanofibers with a semi-IPN structure based on polysulfone/polycyanurate or polysulfone/polycyanurate/polybenzoxazine are discussed. Due to the unique properties of polycyanurates, namely high heat- and chemical resistance to aggressive substances, low dielectric losses, and low water absorption, the resulting electrospun fibers could potentially become useful as components in different advanced materials with improved properties to operate in aggressive environments over a range of temperatures.

Injection of liquid foam through soils is increasingly used in applications such as soil remediation or soil improvement, where it is also crucial to control the liquid relative permeability through the foam-filled soil. We have measured the time dependence of the liquid permeability of granular packings initially filled with liquid foam for different values of the liquid saturation. It is shown that, systematically, permeability increases significantly over time before reaching saturation. We have demonstrated that this evolution is directly related to the coarsening of the liquid foam confined in the pore space. We have shown how the evolution of the liquid permeability can be predicted from the knowledge of the bubble size evolution.

Semidegradable nanoparticles were synthesized in aqueous medium by photoinitiated polymerization-induced self-assembly, using a cleavable hydrophilic copolymer as a steric stabilizer that also served as a macromolecular chain transfer agent (mCTA) for the reversible addition-fragmentation chain transfer (RAFT) polymerization of 2-hydroxypropyl methacrylate (HPMA). This mCTA was obtained by modification of a pH-sensitive poly[(ethylene carbonate)-co-(ethylene oxide)] (PECEO) random copolymer that was end-fitted with a trithiocarbonate moiety. By adjusting the degree of polymerization of HPMA through RAFT, we achieved the synthesis of a series of amphiphilic block copolymers that self-assembled in various morphologies, including spheres, worms, and vesicles. Through characterization by 1H nuclear magnetic resonance, size exclusion chromatography, and transmission electron microscopy, it could be demonstrated that the carbonate linkages of their hydrophilic block and of their steric stabilizer undergo hydrolysis under alkaline conditions. The length of the PHPMA block and the balance between the hydrophilic and hydrophobic blocks are two parameters that have a significant impact on the self-assembly of these particles; a transition from steric to electrostatic stabilization of these nanoparticles could be witnessed during degradation for short PHPMA blocks. In summary, pH-sensitive nanoparticles sterically stabilized by degradable poly(ether-co-ether carbonate) copolymers gave rise under basic conditions to nanoparticles stabilized by electrostatic interaction.

For the first time, the preparation of doubly porous "poly(epsilon-caprolactone)-like" networks through free-radical ring-opening copolymerization of 2-methylene-1,3-dioxepane with divinyl adipate was achieved via a double porogen templating approach. This versatile strategy allowed for the formation of macropores of around 150 mu m generated by removal of sieved and sintered NaCl particles in water, while smaller pores in the 1-10 mu m range were created by phase separation during the copolymerization process through a syneresis mechanism in the presence of a porogenic solvent. The chemical nature of the as-obtained scaffolds was evidenced by Raman spectroscopy. The two distinct porosity levels could be examined by scanning electron microscopy and mercury intrusion porosimetry. The nature of the porogenic solvent as well as its volume proportion and the amount of crosslinking agent in the polymerization feed allowed for finely tuning the porous features of the micropores. The crucial role of the double porosity of such biporous scaffolds on their water uptake and mechanical properties under compression was assessed by comparing them with their monoporous analogues, while their degradability was investigated in different alkaline aqueous media. The double porosity enabled a synergistic effect regarding the water uptake of the resulting scaffolds when compared to their monoporous counterparts. Doubly porous polymeric materials with appropriate mechanical properties were obtained, possessing high compressibility and shape memory behavior upon consecutive compression cycles. Finally, these materials display degradation rates that could be controlled depending on medium pH.

Developing lightweight three-dimensional (3D) materials from biopolymers that exhibit high heat resistance, improved mechanical strength, and low thermal conductivity is crucial for numerous advanced applications. Herein, we successfully fabricated low-density biocomposite aerogels based on chitosan (CS) with exceptional porous structures (porosity exceeding 98%) by utilizing a straightforward approach free of hazardous chemicals. These aerogels combined high mechanical performance, thermal insulation, thermal stability and fire safety. This was achieved through the incorporation of a small amount of graphene nanofillers (G) using an eco-friendly freeze-drying process. The significant influence of the synthesis method as well as the composition and microstructure on the mechanical and thermal insulation performance of G-CS aerogels were highlighted. Two dispersion approaches for graphene were compared: direct addition to the CS solution followed by sonication, and predispersion in water before incorporation into the CS solution. After multidirectional random freezing at different temperatures (-30, -60, and -196 degrees C) and subsequent freeze-drying, the second approach yielded superior mechanical properties in G-CS aerogels. These aerogels showed improved mechanical resistance with increasing graphene content, reaching a Young's modulus of 376 KPa, which was 2.75 times larger than that of pure chitosan aerogel. G(10)-CS showed a remarkable compressive strength to bear loads, approximately 3000 times its weight. Scanning electron microscopy (SEM) analyses revealed that graphene incorporation and reducing the freezing temperature to -60 degrees C transformed the aerogel's microstructure from lamellar to a 3D interconnected honeycomb-like structure, resulting in reduced thermal conductivity (0.038 W m(-1) K-1). The G(10)-CS composite aerogel is expected to be a promising candidate for various practical applications, including thermal and acoustic insulation, energy storage systems, gas detection sensors, biomedical devices, environmental remediation, advanced filtration technologies, and drug delivery.

Organic-inorganic nanocomposites based on heat-resistant crosslinked polycyanurate (PCN) and N-phenylaminopropyl polyhedral oligomeric silsesquioxane (NPAP-POSS), containing eight reactive secondary amino groups, were synthesized using the in situ reactive formation method. Fourier transmission infrared (FTIR) spectroscopy and dynamic differential scanning calorimetry (DSC) methods were used to study the effect of NPAP-POSS on the kinetics of bisphenol E dicyanate ester (DCBE) polycyclotrimerization during the formation of PCN in PCN/NPAP-POSS nanocomposites. The content of the nanofiller was varied from 0.05 to 1.00 wt.%. Based on the results of FTIR spectral studies, the main kinetic peculiarities of PCN formation were found and their changes under the action of NPAP-POSS nanofiller were determined. A significant catalytic effect of NPAP-POSS on the polycyclotrimerization of DCBE was found, which is confirmed by a decrease in the time of the onset of auto-acceleration, an acceleration of the conversion of cyanate groups of DCBE and the formation of triazine cycles of PCN, an increase in the values of the maximum reaction rate, a decrease in the duration of the reaction, etc. The dynamic DSC method also confirmed the catalytic effect of NPAP-POSS on the formation of PCN in the nanocomposites and established the main kinetic characteristics depending on the content of the nanofiller: a significant decrease in the temperature of the exothermic maximum, an increase in the reaction enthalpy, non-monotonic changes in the induction period and reaction rate, etc. From the analysis of the experimental data, it was concluded that the detected changes in the kinetics of the in situ reaction formation of PCN/NPAP-POSS nanocomposites and the recorded catalytic effect of the nanofiller are due to the fact that two chemical processes occur during the synthesis of the nanocomposites: chemical interaction of –O–C≡N groups of DCBE with secondary –NH groups of NPAP-POSS, which led to further embedding of nanoparticles into the resulting polymer matrix and the direct polycyclotrimerization of DCBE with formation of hybrid polycyanurate network. Schemes of the sequential reactions explaining the catalytic effect of the nanofiller in the synthesis of hybrid PCN/NPAP-POSS nanocomposites are proposed. It was concluded that under the selected conditions of the synthesis, the greatest catalytic effect of the nanofiller is manifested at its content of 0.10 wt.%, since for this sample the maximum shift of the reaction exothermic peak towards lower temperatures, the maximum reaction rate, and the minimum induction period and reaction start temperature were recorded. The results of the research make it possible to optimize the synthesis of heat-resistant materials promising for use in special-purpose structures.

In this investigation, a multifunctional visible-light TX-based photosensitizer containing a siloxane moiety (TXS) was designed with a good overall yield of 54%. The addition of a siloxane moiety enabled the incorporation of a TX photosensitizer into a siloxane network by photoinduced sol–gel chemistry, thus avoiding its release. Both liquid 1H and solid-state 29Si NMR measurements undeniably confirmed the formation of photoacids resulting from the photolysis of the TXS/electron acceptor molecule (Iodonium salt), which promoted the photoinduced hydrolysis/condensation of the trimethoxysilane groups of TXS, with a high degree of condensation of its inorganic network. Notably, the laser flash photolysis, fluorescence, and electron paramagnetic resonance spin-trapping (EPR ST) experiments demonstrated that TXS could react with Iod through an electron transfer reaction through its excited states, leading to the formation of radical initiating species. Interestingly, the TXS/Iod was demonstrated to be an efficient photoinitiating system for free-radical (FRP) and cationic (CP) polymerization under LEDs@385, 405, and 455 nm. In particular, whatever the epoxy monomer mixtures used, remarkable final epoxy conversions were achieved up to 100% under air. In this latter case, we demonstrated that both the photoinduced sol–gel process (hydrolysis of trimethoxysilane groups) and the cationic photopolymerization occurred simultaneously.

Infection with antibiotic-resistant bacteria can lead to higher mortality, morbidity, and healthcare costs. An open wound is highly susceptible to microbial infection. To encourage prompt healing, a wound requires a biomimetic dressing material, ideally with hydrophilic and antimicrobial properties. Herein, we propose hydrophobic, cargo-loaded gelatin fibers useable against antibiotic-resistant bacteria. Scanning electron microscopy (SEM) demonstrated the successful formation of the hydrophilic fibers and allowed us to characterize the morphology and the average fiber diameter before and after hydrophobic cargo loading. Differential scanning calorimetry (DSC) measurements indicated that the gelatin-based fibers may have undergone renaturation after electrospinning. Dynamic mechanical analysis (DMA) measurements showed that the presence of hydrophobic cargo enhanced the mechanical properties of the gelatin fibers without the necessity of a crosslinking step. The measurements were then repeated for the fiber when loaded with ciprofloxacin, a hydrophobic antibiotic. The in vitro antibacterial property of the designed ciprofloxacin-loaded gelatin fibers was evaluated by film-diffusion against spectinomycin-resistant Escherichia coli. An inhibitory effect on bacterial growth in a solid medium was observed. These findings demonstrated the potential of the designed fiber to be used as an antimicrobial material for the prevention and treatment of wound infections, particularly those resistant to antibiotic therapy.

In this work, the effect of the method of dispersion of a reactive N-phenylaminopropyl polyhedral oligomeric silsesquioxane (NPAP-POSS, 0.025 wt.%) with eight secondary amino groups, in dicyanate ester of bisphenol E (DCBE) on the chemical processes occurring in reactive DCBE/NPAP-POSS blends during dispersion, as well as on the chemical structure, viscoelastic, thermophysical, and thermal properties of heat-resistant organic-inorganic PCN/NPAP-POSS nanocomposites was investigated. The synthesis of the nanocomposite samples was carried out in two stages. In the first stage, to improve the efficiency of nanofiller dispersion, high-speed mechanical or ultrasonic mixing of NPAP-POSS with DCBE was used at different temperatures (T = 65 °C, T = 165 °C), which ensured the chemical interaction of the components. In the second stage, PCN/NPAP-POSS nanocomposites were synthesized by in situ high-temperature reactive molding by dynamic heating the samples in the temperature range of T = 20–300 °C. Using dynamic mechanical thermal analysis (DMTA) for PCN/NPAP-POSS nanocomposites synthesized by high-speed mechanical or ultrasonic mixing at a temperature of T = 65 °C, an unusually significant increase (by 26.5–28.5 °C compared to PCN) in the glass transition temperature (Tg) of the samples even at ultra-low NPAP-POSS content. This phenomenon demonstrates the so-called nanoscale effect. It was also found that the method of nanofiller dispersion affects the increase (compared to unfilled PCN) of the storage modulus (E’) and other viscoelastic properties, as well as the apparent network density (v) and the apparent average molecular weight (Mc) between crosslinks in the hybrid network matrix of the nanocomposites. Differential scanning calorimetry (DSC) also showed that the dispersion method changes the thermophysical properties of the synthesized PCN/NPAP-POSS nanocomposites. This effect is associated with the formation of additional organic-inorganic crosslinks due to the chemical embedding of NPAP-POSS nanoparticles and the formation of the hybrid PCN/NPAP-POSS network. Fourier transform infrared (FTIR), 1H NMR, and 13C NMR spectroscopy confirmed that during nanofiller dispersion in DCBE/NPAP-POSS reactive blends, a chemical interaction occurs between the –O–C≡N groups of DCBE and the secondary –NH groups of NPAP-POSS. This interaction is confirmed by the appearance of corresponding absorption bands and signals (chemical shifts) in the spectra indicating the formation of intermediate isourea fragments and triazine rings of polycyanurates. It was concluded that ultrasonic dispersion of the nanofiller is the most effective under these synthesis conditions for PCN/NPAP-POSS nanocomposites as it ensures the highest degree of cyanate group conversion in DCBE at the final stages of synthesis (confirmed by DMTA data), thereby extending the range of working temperatures within which the samples retain their mechanical and physical properties. Using thermogravimetric analysis (TGA), it was found that all nanocomposites exhibit high resistance to thermo-oxidative degradation (Td > 440 °C), which is largely unaffected by the method of nanofiller dispersion and is determined by the chemical structure of the densely cross-linked PCN/NPAP-POSS hybrid network.

In this work, reactive 3-aminopropyloligomeric silsesquioxane (AP-OSS) was synthesized and stu­died, and the effect of AP-OSS depending on its content (0.1–1.0 wt.%) on the kinetics of polycyclotri­merization of dicyanate ester of bisphenol E (DCBE) was determined using the dynamic DSC method. AP-OSS was prepared in high yield by the hydrolysis and polycondensation of 3-aminopropyltrimethoxysilane in a mixture of acetonitrile and ethanol, with tetrabutylammonium hydroxide (But4NOH) as a catalyst. The chemical structure of the synthesized AP-OSS was confirmed by the results of FTIR and 1H NMR spectroscopies, as well as by MALDI-TOF method. The FTIR spectra showed broad and intensive stretching absorption bands centered at ν≈ 3431 and ν≈ 3378 cm–1 and bending absorption bands centered at δ≈ 1638 and δ≈ 1599 cm-1 of the N–H in NH2 groups, as well as the absorption bands centered at ν≈1027 and δ≈859 cm–1, attributed to the special characteristic vibrations of the silsesquioxane cage Si–O–Si. MALDI-TOF spectroscopy detected predominantly singly charged protonatedions, indicating that the degree of oligomerization in this silsesquioxane is between n = 3 and 10. It was found that AP-OSS accelerated the DCBE polycyclotrimerization allowing decreasing the final temperature and time of polycyanurate network (PCN) synthesis, the higher content of the AP-OSS the higher acceleration effect has been observed. It was supposed that during the in situ synthesis of the hybrid PCN/AP-OSS nanocomposites, the amino groups on a surface of AP-OSS nanoparticles chemically interact with –O–C≡N-groups of DCBE with formation of isourea fragments providing the covalent embedding of AP-OSS into the growing PCN matrix. Using DSC method, it was found that all synthesized hybrid PCN/AP-OSS nanocomposites possessed high glass transition temperatures (Tg>280oC) and can be classified as thermally stable polymer materials.

Nanocomposites of cyanate ester resin (CER) filled with three different reactive amino-functionalized polyhedral oligomeric silsesquioxane (POSS) were synthesized and characterized. The addition of a small quantity (0.1 wt.%) of amino-POSS chemically grafted to the CER network led to the increasing thermal stability of the CER matrix by 12–15 °C, depending on the type of amino-POSS. A significant increase of the glass transition temperature, Tg (DSC data), and the temperature of α relaxation, Tα (DMTA data), by 45–55 °C of the CER matrix with loading of nanofillers was evidenced. CER/POSS films exhibited a higher storage modulus than that of neat CER in the temperature range investigated. It was evidenced that CER/aminopropylisobutyl (APIB)-POSS, CER/N-phenylaminopropyl (NPAP)-POSS, and CER/aminoethyl aminopropylisobutyl (AEAPIB)-POSS nanocomposites induced a more homogenous α relaxation phenomenon with higher Tα values and an enhanced nanocomposite elastic behavior. The value of the storage modulus, E′, at 25 °C increased from 2.72 GPa for the pure CER matrix to 2.99–3.24 GPa for the nanocomposites with amino-functionalized POSS nanoparticles. Furthermore, CER/amino-POSS nanocomposites possessed a higher specific surface area, gas permeability (CO2, He), and diffusion coefficients (CO2) values than those for neat CER, due to an increasing free volume of the nanocomposites studied that is very important for their gas transport properties. Permeability grew by about 2 (He) and 3.5–4 times (CO2), respectively, and the diffusion coefficient of CO2 increased approximately twice for CER/amino-POSS nanocomposites in comparison with the neat CER network. The efficiency of amino-functionalized POSS in improving the thermal and transport properties of the CER/amino-POSS nanocomposites increased in a raw of reactive POSS containing one primary (APIB-POSS) < eight secondary (NPAP-POSS) < one secondary and one primary (AEAPIB-POSS) amino groups. APIB-POSS had the least strongly pronounced effect, since it could form covalent bonds with the CER network only by a reaction of one -NH2 group, while AEAPIB-POSS displayed the most highly marked effect, since it could easily be incorporated into the CER network via a reaction of –NH2 and –NH– groups with –O–C≡N groups from CER.

Nanocomposites of cyanate ester resin (CER) filled with three different reactive amino-functionalized polyhedral oligomeric silsesquioxane (POSS) were synthesized and characterized. The addition of a small quantity (0.1 wt.%) of amino-POSS chemically grafted to the CER network led to increasing thermal stability of CER matrix. A significant increase of the glass transition temperature, Tg (DSC data), and the temperature of α relaxation, Tα (DMTA data), by 45-55 оС of CER matrix with loading of nanofillers was evidenced. CER/POSS films exhibited a higher storage modulus than that of neat CER in the temperature range investigated. It was evidenced that CER/aminopropylisobutyl (APIB)-POSS, CER/N-phenylaminopropyl (NPAP)-POSS, and CER/aminoethyl aminopropylisobutyl (AEAPIB)-POSS nanocomposites induced a more homogenous α relaxation phenomenon with higher Tα values and an enhanced nanocomposite elastic behavior. Furthermore, CER/amino-POSS nanocomposites possessed higher specific surface area, gas permeability (CO2, He), and diffusion coefficients (CO2) values than those for neat CER, due to increasing free volume of the nanocomposites studied that is very important for their gas transport properties. Permeability grew respectively by about 2 (He) and 3.5-4 times (СО2), and diffusion coefficient of CO2 increased approximately twice for CER/amino-POSS nanocomposites in comparison with the neat CER network. The efficiency of amino-functionalized POSS in improving the thermal and transport properties of the CER/amino-POSS nanocomposites increased in a raw of reactive POSS containing one primary (APIB-POSS) < eight secondary (NPAP-POSS) < one secondary and one primary (AEAPIB-POSS) amino groups. APIB-POSS had the least strongly pronounced effect, since it could form covalent bonds with the CER network only by reaction of one –NH2 group, while AEAPIB-POSS displayed the most highly marked effect, since it could easily be incorporated into the CER network via reaction of –NH2 and –NH– groups with –O–C≡N groups from CER.