Reactive compatibilization and fracture behavior in nylon 6/VLDPE blends

Low-density polyethylene was modified to incorporate aniline moieties by reactive processing with 4-aminobenzenesulfonyl azide. Under melt-processing conditions, the loss of nitrogen produces a sulfonyl nitrene which, in the singlet state, interacts with the substrate primarily by C-H insertion. Polymeric blends prepared from aniline-grafted polyethylene and nylon-66 showed improved tensile and impact properties over and above nylon blended with virgin polyethylene.

Section: Resultsmentioning

confidence: 99%

Sulfonyl azides—an alternative route to polyolefin modification

Bateman

2002

“…This makes possible practical application of the usual nonfilled, as well as complex and composite PVACGs as, e.g., carriers of immobilized enzymes and cells, macroporous supports of immunosorbents, drug delivery matrices, etc. [3][4][5][9][10][11][12][13][14] Such pores do exist in the structure of vof-PVACGs, i.e., this general morphological feature of macroporous PVA cryogels is retained in the oilfilled composites, too.…”

Section: Morphological Features Of Composite Pva Cryogels Filled Withmentioning

confidence: 99%

“…3,5,[9][10][11][12][13] and also as materials of biomedical interest, e.g., gels for controlled drug release, covers on wounds and burns, artificial cartilages, components of model heart implants, phantoms for calibration of NMR tomographs, and ultrasound equipment. [1][2][3][4][5][14][15][16][17][18] Along with PVACGs originating simply from the polymer solutions without any additives, complex and filled (composite) PVA cryogels were prepared, investigated, and described. 3,5,12 The former contain various soluble compounds, both of low-and highmolecular weight, whereas the latter include such dispersed matter, as solid particles, semi-solid gel granules, microbial cells, air bubbles, etc., entrapped (immobilized) in the matrix of continuous phasemacroporous PVA cryogel.…”

Section: Introductionmentioning

confidence: 99%

Cryostructuring of polymer systems. XXX. Poly(vinyl alcohol)‐based composite cryogels filled with small disperse oil droplets: A gel system capable of mechanically induced releasing of the lipophilic constituents

Podorozhko

Korlyukov

Lozinsky

2010

Composite heterophase poly(vinyl alcohol) (PVA) cryogels containing entrapped small droplets of Vaseline oil have been prepared and studied. Such oilfilled cryogels were formed via freeze-thaw treatment of freshly prepared oil-in-water emulsions containing varied volume fraction of lipophilic phase, and the influence of the amount of this phase, as well as the effects of freezing conditions on the physicomechanical (shear moduli) and thermal (gel fusion temperature and fusion enthalpy) characteristics of resulting composites have been explored. It was shown that over certain range of PVA concentrations in aqueous phase and a range of volume fraction of the hydrophobic phase its microdroplets performed as ''active'' fillers causing an increase in both the gel strength and the heat endurance of composites. The light microscopy data on the morphological features of such filled PVA cryogels revealed the effect of diminution in size of oil droplets entrapped in the gel matrix as compared with the initial emulsions. This effect can be explained by the disintegrating action of crushing and shear stresses arising upon the system freezing and growth of ice crystals. The oil-filled PVA cryogels were found to be capable of gradually releasing the lipophilic constituents (the Rose hips oil, in this case) in response to the cyclic mechanical compression.

“…Such microcrystallytes perform as junction knots in the 3D polymeric network. [17][18][19][20] The most studied among similar freeze-thawinduced noncovalent gel systems are the PVA cryogels (cryoPVAGs) that also attract considerable attention regarding their practical use, in particular, as materials of biomedical application (e.g., as gel bases of artificial cartilages or certain soft tissues) 1,3,21,22 and in biotechnology (e.g., as matrices for the immobilization of biomolecules and cells). 2,4,23,24 In this respect, of special interest are the cryoPVAGs formed not only from PVA solutions without any foreign additives, but the complex and composite cryoP-VAGs containing extra soluble or nonsoluble (fillers) components, capable of changing significantly the properties of cryoPVAGs.…”

Section: Introductionmentioning

confidence: 99%

“…2,4,23,24 In this respect, of special interest are the cryoPVAGs formed not only from PVA solutions without any foreign additives, but the complex and composite cryoP-VAGs containing extra soluble or nonsoluble (fillers) components, capable of changing significantly the properties of cryoPVAGs. 2,4,21,22 Thereupon, the aim of this work was the preparation and study of novel organic-inorganic heterophase cryoPVAGs, when tetramethoxysilane (TMOS) was introduced in to the aqueous polymer solution prior to its freezing. TMOS is known to transform to polysicilic acid and then to silica structures during hydrolysis in aqueous media.…”

Section: Introductionmentioning

confidence: 99%

Cryostructuring of polymer systems. XXVI. Heterophase organic–inorganic cryogels prepared via freezing–thawing of aqueous solutions of poly(vinyl alcohol) with added tetramethoxysilane

Lozinsky¹,

Bakeeva²,

Presnyak³

et al. 2007

Composite heterophase organic-inorganic hybrid cryogels of poly(vinyl alcohol) (PVA) containing silica constituents were prepared and studied. Such constituents were formed in the course of hydrolytic polycondensation (sol-gel process) of tetramethoxysilane (TMOS) introduced in to the aqueous polymer solution prior to its freezethaw treatment. It was shown that moderate (over the range of À15 to À308C) freezing, then frozen storage, and subsequent thawing of the water/PVA/TMOS systems resulted in the formation of macroporous composite cryogels filled with dispersed silica particles (discrete phase). The continuous phase of such gel materials represents the supramolecular PVA network, which is supposed to be additionally cured with the silicon-containing oligomeric cross agents formed from TMOS in the course of hydrolytic polycondensation. The incorporated silica components influenced the morphology of cryogels. The effects of significant increase in gel strength and heat resistance with increasing TMOS concentration in the initial feed and with thawing rate decreasing have also been observed.