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Poly(methacrylic acid) brushes have been prepared utilizing the “grafting from” technique and a living radical synthesis route using a two stage process. Firstly a poly(1-ethoxyethyl methacrylate) brush was synthesized by atom transfer radical polymerization and then thermally decomposed to poly(methacrylic acid). The swelling behaviour of the weak polyacid brush was investigated as a function of...
Block copolymer modified epoxy resins have generated significant interest since it was demonstrated that the combination could lead to nanostructured thermosets through self-assembly. Over moderate to high polymer concentration the system behaves as expected for a block copolymer in a solvent selective for one block. Two types of copolymers have been studied: non-reactive and reactive modifiers. Morphologies...
A polyurethane (PU) network based on vegetable derived polyol has been characterised and compared to a synthetic based network. Fracture mechanics studies showed the lowest tear strength for the vegetable networks, which decreased as molecular weight of the vegetable based polyol increased. Swelling studies were carried out to determine the molecular weight between crosslinks and polymer networks...
Correlations between polyurethane foam formulation and foam aging are shown to simplify when sufficient data are available to eliminate casual relationships. The numerous factors that are purported to result in faster or slower foam aging are shown to primarily reflect how those factors influence polyurethane hard segment structure. Specifically, changes in formulation that results in better phase...
The morphology of as-cast and annealed thin films of four symmetric semicrystalline block copolymers on mica was investigated by tapping mode atomic force microscopy (AFM) and grazing incidence X-ray diffraction (XRD). It is found that the morphology of the thin films is dependent on chain length of oxyethylene/oxybutylene block copolymers. The as-cast thin films of the shorter E m B n...
The isothermal crystallization kinetics and the melting behavior of block copolymers of poly(ethylene oxide) and poly(1,2-butylene oxide) were studied by means of differential scanning calorimetry and rheometry to test the validity of rheological methods. The copolymers had different block lengths (hence different melt structures) and different block architectures (diblock EB and triblock EBE and...
Three nearly symmetrical ternary systems made of ternary blends of polystyrene, polyisoprene, polystyrene—block—polyisoprene copolymer have been investigated by small angle X-ray scattering (SAXS). The molecular weights of the homopolymers were varied, keeping the diblock length constant, to obtain ratios of homopolymer to diblock length, α, of 0.19, 0.38 and 0.74. For all experimental phase diagrams...
The crystallization behavior of poly(oxyethylene)-b-poly(oxybutylene) block copolymers with different compositions, morphologies and architectures (E m B n diblock copolymers and E m B n E m , B n E m B n triblock copolymers) were investigated and the effect of volume fraction and architecture on the crystallization temperature (T ...
The phase behavior of a Poly(2,6-dimethyl-1,4-phenylene ether) (PPE)/diglycidyl ether of bisphenol A type epoxy (DGEBA)/diethyltoluenediamine (DETDA) blend during reaction induced phase separation is predicted using Flory-Huggins theory. DGEBA and DETDA are treated as a single pseudo-component in order to reflect the crosslinking polymerisation that occurs between them, and both the PPE and the DGEBA/DETDA...
The compression behaviour of a range of unoriented linear and branched polyethylenes was investigated using the technique of simultaneous small- and wide-angle X-ray scattering during deformation. Interlamellar deformation mechanisms, including simultaneous shear and rotation of lamellar stacks, were followed by crystallographic deformation mechanisms, including (100)[001] chain slip and a martensitic...
The cold drawing behaviour of a range of unoriented linear polyethylenes was investigated using the technique of simultaneous small- and wide-angle X-ray scattering during deformation. The influences of molecular weight and thermal history were studied. The role of both variables was found to be highly important since by altering the percentage crystallinity they influenced the relative amounts...
The present study was undertaken to investigate the mechanism for primary nucleation in polymer crystallization. Previous studies in this area have not been conclusive. Experiments on polypropylene with long induction times, studied by small- and wide-angle X-ray scattering (SAXS and WAXS), reveal the onset of long-range ordering prior to crystal growth. Rapid crystallizations studied by melt extrusion...
SAXS/WAXS/d.s.c. at the SRS has been used to follow the melting and recrystallization of isotactic polypropylene (iPP). The time correlation is perfect between the three techniques which show good agreement with respect to crystallinity and kinetics. The degree of crystallinity and the lamellar thickness of iPP have been calculated from SAXS and WAXS patterns, obtained simultaneously during melting...
The cold drawing behaviour of a range of polyethylene copolymers was investigated using the technique of simultaneous small- and wide-angle X-ray scattering (SAXS and WAXS, respectively) during deformation. The influence of branch amount, branch length and lamellar population were studied. Branch length was found to be unimportant. Increasing branch content lowered the percentage crystallinity...
Crystalline cyclic poly(oxyethylene)s of number-average molar mass 1000, 1500, 2000 and 3000 g mol -1 were studied by high-frequency and low-frequency laser-Raman spectroscopy, wide-angle (WAXS) and small-angle (SAXS) X-ray scattering, and differential scanning calorimetry (d.s.c.). Comparison was made with the properties of corresponding linear poly(oxyethylene) dimethyl ethers. The...
Forced-adiabatic, FT i.r. spectroscopy has been employed to simultaneously monitor polymerization and microphase separation on model flexible polyurethane foam systems. The following combinations of hydroxy functional components were investigated: (1) polyether-polyol and water; (2) polyether-polyol and deuterium oxide; (3) polyether-monol and water; and (4) polyether-monol and deuterium oxide. ...
Crystallization of polymer chains between hard glassy walls or between amorphous domains in a nanoscale lamellar structure has been observed using simultaneous small-angle and wide-angle X-ray scattering (SAXS/WAXS). Semicrystalline symmetric diblock copolymers containing poly(ethylene) (PE) and a room-temperature glassy or amorphous component were shear oriented in the high temperature lamellar melt,...
A range of cyclic poly(oxyethylene)s, (OCH 2 CH 2 ) m , with m in the range 23-68, corresponding to rings of 69-204 chain atoms, have been prepared by a modified tosylation method that gave c. 75 wt% yields. Gel permeation chromatography and nuclear magnetic resonance were used to monitor the cyclization and purification procedures. Small-angle X-ray studies provided a useful...
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