Propylglycidyl Ether Research Articles

Unraveling the ablative behavior through the design of a POSS-Benzoxazine/EPDM network under harsh environments

In order to meet the demands of the insulation layer in the swiftly advancing aerospace thermal protection system and enhance the ablation resistance of ethylene propylene diene rubber (EPDM) insulation layer, a novel EPDM ablation resistance composite was designed by integrating benzoxazine fine-tuned with octal (propyl glycidyl ether) polyhedral oligomeric silsesquioxane (BA-POSS) into the network structure of EPDM. The resulting composite exhibited a more densely cross-linked EPDM/BA-POSS network, consequently augmenting both the mechanical and ablation properties of the EPDM ablation resistance composite. The cross-linking density and tensile strength of EPDM/BA-POSS composite with 18 phr (parts per hundred rubber) BA-POSS increased by 78.4% and 30.7%, respectively, and the linear ablation rate significantly reduced by 47.7%, compared with EPDM composite without BA-POSS. Additionally, the ablation mechanism of EPDM/BA-POSS composites was elucidated through an investigation of the thermo-chemical transformation and analysis of the ablated carbon layer. This study contributes novel insights and methodologies for the future design of low-density rocket motor insulation compounds that offer cost efficiency, enhanced functionality, and wider applicability.

POSS‐modified ammonium polyphosphate for improving flame retardant of epoxy resins

AbstractAn innovative phosphorus‐silicone flame retardant (KAPP‐OGPOSS) was prepared by grafting octa (propyl glycidyl ether) polyhedral oligomeric silsesquioxane (OGPOSS) on ammonium polyphosphate (APP) through silane coupling agent (KH‐550). The chemical structure, morphology, flame retardancy, and mechanism of the obtained materials were comprehensively investigated. TG results demonstrated that EP with 15 wt% KAPP‐OGPOSS produced a char residue of 42.6% at 700°C, which is three times that of pure EP. The flame retardant tests showed that the limiting oxygen index value of EP/15 wt% KAPP‐OGPOSS was 30.6% (67.7% higher than that of neat EP) and its UL‐94 grade reached to V‐0 rating. Cone calorimeter testing indicated that the incorporation of 15 wt% KAPP‐OGPOSS to EP significantly reduced heat, smoke, CO, and CO2 release by 79%, 83%, 80%, and 82.5%, respectively. The modification of APP with OGPOSS was also beneficial for the improvement of the char yield and density of char. A flame retardant mechanism was revealed according to the investigation into the char residue. This modified approach provided an innovative yet practical means of enhancing the flame retardant properties of EP.

MWCNT grafted with POSS-based novel flame retardant-filled epoxy resin nanocomposite: fabrication, mechanical properties, and flammability

ABSTRACT In the present work, we prepared the MWCNT-L-POSS from the grafting reaction between octa (propylglycidyl ether) polyhedral oligomeric silsesquioxane (POSS) and multi-wall carbon nanotubes (MWCNT). The certainty of this product was confirmed by using the Fourier-transform infrared spectroscopy (FTIR) technique. The MWCNT-L-POSS was applied as an additive for epoxy resin which was cured at room temperature. The main behaviors of the fabricated composite were studied including flexural strength and flammability. The flexural strength increase by 24.8% from 86.8 to 108.3 Mpa. The flame retardant of epoxy resin was improved by adding MWCNT-L-POSS with reducing the value of total smoke release (TSR), total heat release (THR), and peak heat release rate (PHRR).

POSS-functionalized graphene oxide hybrids with improved dispersive and smoke-suppressive properties for epoxy flame-retardant application

Functionalized graphene oxide sheets (FGO) with improved dispersive and smoke-suppressive properties were synthesized by covalently grafting octa (propyl glycidyl ether) polyhedral oligomeric silsesquioxane on graphene oxide sheets (GO) with γ-aminopropyl triethoxysilane as a chemical bridge. The good dispersion of FGO sheets in the epoxy resin (EP) matrix endowed EP composites with stable thermal resistance, enhanced tensile and smoke-suppressive properties. Cone calorimeter tests indicated that the addition of 0.7 wt% FGO sheets to EP composites reduced the peak of heat release rate, total heat release, and total smoke release by 49.7%, 34.3%, and 41.5%, respectively. Two important effects that originated from FGO promoted this improvement; that is, well-dispersed FGO sheets exhibited a tortuous effect by lengthening the heat path and inhibiting heat diffusion in the EP matrix, and the increase in char residue and the reduction in gas volatiles confirmed the barrier effect of FGO sheets by forming protective char structures on the surface of the matrix, which restrained smoke release. This method provided a feasible concept for effectively enhancing the flame retardancy of EP composites by combining the characteristics of graphene and polyhedral oligosilsesquioxane through the construction of effective interfacial interactions.

Synchrotron X-ray scattering and photon correlation spectroscopy studies on thin film morphology details and structural changes of an amorphous-crystalline brush diblock copolymer

Abstract We investigated structural details and temperature-induced structural changes of an amorphous-crystalline brush diblock copolymer, poly(3-((6-((7-(9H-carbazol-9-yl)heptanoyl)oxy)hexyl)thio)propyl glycidyl ether) 60 - b -poly(glycidyl 12-((3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,10-heptadecafluorodecyl)oxy)-12-oxododecanoate) 20 (PGK 60 -PGF 20 ) in nanoscale thin films using synchrotron grazing incidence X-ray scattering (GIXS) and X-ray photon correlation spectroscopy (XPCS). Interestingly, the diblock copolymer was found to form a mixture of two different hexagonal cylinder structures (HEX1 and HEX2) where the PGF cylinders were aligned in the film plane. HEX1 was composed of PGF cylinders with higher population of crystals while HEX2 consisted of PGF cylinders with lower population of crystals. Surprisingly, the PGF block chains favorably self-assembled because of strong lateral interactions in the bristles, forming vertical multibilayer structure with partial interdigitation even in the highly confined cylindrical geometry. In heating run up to 340 K, some fraction of HEX2 was transformed to HEX1 via cold crystallization. In contrast, HEX1 was transformed to HEX2 above 340 K because of melting of the PGF crystals. The XPCS analysis found that the HEX structural changes associated with the cold crystallization in the PGF cylinder domains took place with relatively fast dynamics. The HEX structural changes associated with melting of the PGF crystals in the cylinder domains occurred with relatively slow dynamics; this unusual dynamics of structural changes might be attributed to a high energy melting process of PGF crystals against strong lateral interactions of the bristles.

Preparation of Organic-Silica Hybrid Monolith with Anion Exchange/Hydrophilic Interaction Mixed-Mode Via Epoxy–Amine Ring-Opening Polymerization Using Polyethylenimine as Functional Monomer

Polyethylenimine (PEI) and 2,4,6,8-tetramethyl-2,4,6,8-tetrakis(propyl glycidyl ether)cyclotetrasiloxane (POSS–epoxy) were used as precursors for the preparation of organic-silica hybrid monolithic columns (PEI–POSS monolith) via epoxy–amine ring-opening polymerization (ROP). The high density of amine groups in PEI provides rich chromatographic interaction sites for the polar or acidic analytes in hydrophilic interaction (HILIC) and weak anion exchange (WAX) mechanisms. The column preparation conditions, such as the porogens, solvent and reaction temperature, were systematically investigated according to the morphology, permeability and column efficiency. The separation mechanisms of HILIC and WAX were evaluated with neutral polar compounds and halogen benzoic acids. Owing to the existence of reactive amine groups on the matrix surface, the PEI–POSS monolith is also an ideal starting material for the preparation of HILIC or strong anionic exchange (SAX) stationary phases by modification. The modification of PEI–POSS monoliths with iodomethane or bromoacetic acid via the nucleophilic substitution reaction could achieve the retention mechanisms of SAX or zwitterionic HILIC, respectively.

Complex of cisplatin with biocompatible poly(ethylene glycol) with pendant carboxyl groups for the effective treatment of liver cancer

ABSTRACTCisplatin was incorporated into polymeric carriers through the coordination of Pt with the carboxylic groups of methoxy‐poly(ethylene glycol) (mPEG)‐block‐poly[(2‐carboxy‐ethylsulfanyl)‐propyl glycidyl ether] (PCPGE). The mPEG‐b‐PCPGE/Pt complexes with a Pt content of 14 wt % could self‐assemble into spheric micelles with diameter of about 80 nm in aqueous solution. The effective internalization of the polymer platinum micelles by the cells via an endocytosis mechanism was confirmed by confocal laser scanning microscopy and flow cytometry. The antitumor activity of the polymeric micelles was similar to that of cisplatin in vitro. The in vivo blood clearance of platinum was studied, and the results show that the micelles exhibited longer blood circulation than the free cisplatin. The biodistribution of cisplatin and its micelles in mice was studied through the measurement of the Pt content in plasma, organs, and tumors, especially in tumor cell DNA. Their antitumor activity in vivo, assessed in mice bearing H22 liver cancers, showed that the micelles exhibited greater antitumor efficacy than free cisplatin. Therefore, this polymer platinum micelle is a promising candidate as a smart antitumor drug carrier for malignancy therapy in future clinical applications. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40764.

High‐performance nanocomposites derived from allyl‐terminated benzoxazine and octakis(propylglycidyl ether) polyhedral oligomeric silsesquioxane

AbstractIn this study, we used the Mannich condensation of bisphenol A, formaldehyde, and allylamine to synthesize a allyl‐terminated benzoxazine (VB‐a), which can be polymerized through ring opening polymerization. We used this VB‐a monomer, blended with octakis(propylglycidyl ether) polyhedral oligomeric silsesquioxane (OG‐POSS), to prepare polybenzoxazine/POSS nanocomposites. Differential scanning calorimetry and Fourier transform infrared (FTIR) spectroscopy revealed that the mechanism of the crosslinking reaction leading to the formation of the organic/inorganic network involved two steps: (i) ring opening and allyl polymerizations of VB‐a and (ii) subsequent reactions between the in situ‐formed phenolic hydroxyl groups of VB‐a and the epoxide groups of OG‐POSS. Dynamic mechanical analysis revealed that the nanocomposites had higher mechanical properties than did the control VB‐a. In the glassy state, nanocomposites containing less than 10 wt % POSS displayed enhanced storage moduli; those of the nanocomposites containing greater than 10 wt % POSS were relatively low, due to aggregation, as determined using scanningelectron microscopy. Thermogravimetric analysis indicated that the nanocomposites possessed greater thermal stability than that of the pure polymer. FTIR spectroscopic analysis revealed the presence of hydrogen bonding between the siloxane groups of POSS and the OH groups of the polybenzoxazine. POLYM. COMPOS., 2011. © 2011 Society of Plastics Engineers

Organic–inorganic hybrid nanocomposites involving novolac resin and polyhedral oligomeric silsesquioxane

Octa(propylglycidyl ether) polyhedral oligomeric silsesquioxane (OpePOSS) was employed as a nanocrosslinker of novolac resin to prepare the organic–inorganic networks. The crosslinking reaction was investigated by means of Fourier transform infrared (FTIR) and nuclear magnetic resonance (NMR) spectroscopy via model reaction. Thermal analyses indicate that the glass transition temperatures ( T g’s) and thermal stability of the organic–inorganic networks increased with increasing the content of POSS. Contact angle measurements show that the organic–inorganic nanocomposites displayed a significant enhancement in surface hydrophobicity as well as reduction in surface free energy. The improvement in surface properties was ascribed to the presence of POSS moiety in place of polar component of phenolic thermosets.

Inorganic–organic interpenetrating polymer networks involving polyhedral oligomeric silsesquioxane and poly(ethylene oxide)

A novel organic–inorganic interpenetrating polymer network (IPN) was prepared via in situ crosslinking between octa(propylglycidyl ether) polyhedral oligomeric silsesquioxane (OpePOSS) and 2,2-bis(4-hydroxyphenyl)propane in the presence of poly(ethylene oxide) (PEO). The miscibility and intermolecular specific interactions of the IPNs were investigated by means of differential scanning calorimetry (DSC), transmission electron microscopy (TEM) and Fourier transform infrared (FTIR) spectroscopy. In view of the results of calorimetric analysis and morphological observation, it is judged that the components of the organic–inorganic IPNs are fully miscible. The FTIR spectroscopy shows that there are inter-component hydrogen bonding interactions between the POSS network and PEO. The measurements of static contact angle show that the hydrophilicity (and/or the surface free energy) of the organic–inorganic IPNs increased with the addition of the miscible and water-soluble polymer ( i.e., PEO). Thermogravimetric analysis (TGA) shows that the thermal stability of the IPNs was quite dependent on the mass ratios of the POSS network to PEO.

Poly( N-isopropylacrylamide) nanocrosslinked by polyhedral oligomeric silsesquioxane: Temperature-responsive behavior of hydrogels

Octa(propylglycidyl ether) polyhedral oligomeric silsesquioxane (OpePOSS) was used as a nanocrosslinking agent to prepare the crosslinked poly( N-isopropylacrylamide) (PNIPAM) networks with POSS content up to 50 wt%. The inter-component crosslinking was achieved via the reaction between N H moieties in amide group of PNIPAM and epoxide groups of OpePOSS. When the organic–inorganic nanocomposites were swollen in water the POSS-crosslinked PNIPAM exhibited the characteristics of hydrogels. With the moderate contents of POSS, the POSS-containing hybrid hydrogels displayed much faster response rates in swelling, deswelling and reswelling experiments than the PNIPAM hydrogels prepared via the free radical copolymerization of N-isopropylacrylamide (NIPAM) and N , N ′ -methylenebisacrylamide (viz. the conventional crosslinker). The improved hydrogel properties have been interpreted on the basis of the formation of the nanosized hydrophobic microdomains around the POSS moieties (i.e., the nanocrosslinking sites).

Back Cover: Macromol. Chem. Phys. 20/2006

Back Cover: Octa(propylglycidyl ether) polyhedral oligomeric silsesquioxane (OpePOSS) was incorporated into polyurethane networks through the inter‐component reactions between polyurethane networks and OpePOSS. The POSS‐modified polyurethane networks displayed improved thermal, tensile and surface properties compared to polyurethane. Further details can be found in the Full Paper by Y. Liu, Y. Ni, and S. Zheng* on page 1842.

Inorganic–organic nanocomposites of polybenzoxazine with octa(propylglycidyl ether) polyhedral oligomeric silsesquioxane

AbstractOcta(propylglycidyl ether) polyhedral oligomeric silsesquioxane (OpePOSS) was used to prepare the polybenzoxazine (PBA‐a) nanocomposites containing polyhedral oligomeric silsesquioxane (POSS). The crosslinking reactions involved with the formation of the organic–inorganic networks can be divided into the two types: (1) the ring‐opening polymerization of benzoxazine and (2) the subsequent reaction between the in situ formed phenolic hydroxyls of PBA‐a and the epoxide groups of OpePOSS. The morphology of the nanocomposites was investigated by means of scanning electron microscopy, transmission electron microscopy, and atomic force microscopy. Differential scanning calorimetry and dynamic mechanical analysis showed that the nanocomposites displayed higher glass‐transition temperatures than the control PBA‐a. In the glassy state, the nanocomposites containing less than 30 wt % POSS displayed an enhanced storage modulus, whereas the storage moduli of the nanocomposites containing more than 30 wt % POSS were lower than that of the control PBA‐a. The dynamic mechanical analysis results showed that all the nanocomposites exhibited enhanced storage moduli in the rubbery states, which was ascribed to the two major factors, that is, the nanoreinforcement effect of POSS cages and the additional crosslinking degree resulting from the intercomponent reactions between PBA‐a and OpePOSS. Thermogravimetric analysis indicated that the nanocomposites displayed improved thermal stability. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 1168–1181, 2006

Epoxy nanocomposites with octa(propylglycidyl ether) polyhedral oligomeric silsesquioxane

The POSS-containing nanocomposites of epoxy resin were prepared via the co-curing reaction between octa(propylglycidyl ether) polyhedral oligomeric silsesquioxane (OpePOSS) and the precursors of epoxy resin. The curing reactions were started from the initially homogeneous ternary solution of diglycidyl ether of bisphenol A (DGEBA), 4,4′-Diaminodiphenylmethane (DDM) and OpePOSS. The nanocomposites containing up to 40 wt% of POSS were obtained. The homogeneous dispersion of POSS cages in the epoxy matrices was evidenced by scanning electronic microscopy (SEM), transmission electronic microscopy (TEM) and atomic force microscopy (AFM). Differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA) showed that at the lower POSS concentrations (<30 wt%) the glass transition temperatures ( T gs) of the nanocomposites almost remained invariant whereas the nanocomposites containing POSS more than 40 wt% displayed the lower T gs than the control epoxy. The DMA results show that the moduli of the nanocomposites in glass and rubbery states are significantly higher than those of the control epoxy, indicating the nanoreinforcement effect of POSS cages. Thermogravimetric analysis (TGA) indicates that the thermal stability of the polymer matrix was not sacrificed by introducing a small amount of POSS, whereas the properties of oxidation resistance of the materials were significantly enhanced. The improved thermal stability could be ascribed to the nanoscaled dispersion of POSS cages and the formation of tether structure of POSS cages with epoxy matrix.

Poly(4‐vinylpyridine) Nanocrosslinked by Polyhedral Oligomeric Silsesquioxane

AbstractSummary: Octa(propylglycidyl ether) polyhedral oligomeric silsesquioxane (OpePOSS) was used as the crosslinking agent to prepare the nanocrosslinked poly(4‐vinylpyridine) (P4VP) with POSS content up to 55.2 wt.‐%. The formation of the crosslinked structure is ascribed to the macromolecular reaction between pyridine rings of P4VP and epoxide groups of OpePOSS. The POSS‐crosslinked P4VP displayed enhanced glass transition temperatures (Tgs) and an improved thermal stability in terms of the results of thermal analysis.Crosslinking of poly(4‐vinylpyridine) with octa(propylglycidyl ether) polyhedral oligomeric silsesquioxane.magnified imageCrosslinking of poly(4‐vinylpyridine) with octa(propylglycidyl ether) polyhedral oligomeric silsesquioxane.

Association properties of poly(ethylene oxide) modified by pendant aliphatic groups

Series of copolymers ethylene oxide and alkylglycidyl ether (EO-co-AGE), ethylene oxide-3,3-di(alkoxymethyl)propyl glycidyl ether (EO-co-DAGE) and poly(alkyl glycidyl ether) ((POM/POE)–PAGE) have been synthesised, as associating water-soluble polymers, where the hydrophobic substituents (less than 1% mole fraction) are, respectively, randomly distributed along the chain or present as dimers or as long sequences. The synthesis of initial hydrophobic monomers and the copolymer preparation are shortly described. The associative properties of these new associating samples were studied as functions of length, distribution, mole fraction of hydrophobes and polymer concentration, using fluorescence, light scattering and viscosimetry. Generally, these comb-like associating polymers do not exhibit thickening properties as good as those of the equivalent telechelic polymers of the same chemical composition. This difference is attributed to the formation of intra-molecular hydrophobic association favoured in cases of comb structure with respect to the telechelic ones. However, a great influence of the sequentiality of the hydrophobe distribution was observed.