Polychloroprene Rubber/Reduced Graphene Oxide (RGO) Nanomembranes for Pervaporation Separation of Azeotropic Mixtures

Chloroprene rubber is a high performance elastomer with remarkable ageing, heat and oil resistance. A new class of elastomeric nanocomposite was prepared by incorporating reduced graphene oxide (RGO) into chloroprene rubber (CR). RGO is synthesised from natural graphite, through GO route via Hummer's method. This paper focuses on the influence of reduced graphene oxide on chloroprene rubber based elastomeric composites and their pervaporation separation of azeotropic liquid mixtures. The effect of concentration of RGO on separation factor, pervaporation separation index (PSI) and flux of the membranes were analysed. Chloroprene loaded with 0.9 phr (parts per hundred rubber) RGO shows an improved permeation rate among all other membranes while chloroform/acetone (80/20) azeotropic liquid mixture was used as feed solution. Flux increases with increasing the concentration of filler, reaches an optimum value and then decreases. Interestingly PSI also shows similar trend

Hydrophilic Nanocomposite Membranes for the Pervaporation Separation of Water - Ethanol Azeotropic Mixtures

Bentonite nanoclay reinforced Poly (vinyl alcohol) (PVA) nanocomposite membranes were used for the separation of azeotropic composition of water – ethanol mixtures by pervaporation process. Fourier – transform infrared (FTIR) spectroscopic studies revealed the interaction of bentonite nanoclay and the PVA matrix. The dispersion and distribution of nanoclay in the polymer matrix was demonstrated by transmission electron microscopic analysis (TEM). The intrinsic membrane properties with filler loading were also investigated. The results indicate that the hydrophilic nature of the nanoclay influenced the pervaporation to a greater extent. The hydrophilic nature and surface roughness of the nanocomposite membranes was analyzed by atomic force microscopic (AFM) analysis. The pervaporation process illustrates that the permeation flux increases and the separation factor decreases with nanoclay loading. The instrinsic selectivity, which reflects the membrane performance was maximum for 1 wt% clay loaded membranes. PVA with 1 wt% nanoclay loading showed better pervaporation performance. The separation factor of the 1 wt% nanoclay membranes increased to 13, i.e. nearly 4 times more than that of neat PVA membranes. Membrane selectivity also increased to 254% than that of pristine PVA membranes. Thus at lower filler loading, maximum separation was achieved. The increase in nanoclay loading is favorable to improve intrinsic permeance at the cost of decrease in selectivit

Transport of organic solvents through natural rubber/nitrile rubber/organically modified montmorillonite nanocomposites

International audienceThe article describes the transport phenomenon of some commonly used laboratory organic solvents which differ in their solubility parameter value through polymer blend nanocomposites membrane prepared by melt mixing. The three solvents that were used are hexane, toluene and xylene which differed widely in their solubility parameter values. The motivation for the study was to know the effect of solubility parameter on the diffusion transport properties of NR/NBR (natural rubber/nitrile rubber) blends. The solvent uptake, diffusion, sorption and permeation constants were investigated and were found to decrease with organically modified montmorillonite (OMt) content at lower loading. The mode of transport through NR/NBR nano-composites was found to be anomalous. The difference in solubility parameter value greatly influenced the transport properties. The dependence of various properties on OMt content was supported by morphological analysis data. The effect of blend ratio, solvent size and OMt loading on the diffusion of aromatic and aliphatic solvents through NR/ NBR blend systems were investigated. The swelling coefficient values also decreased upon the addition of fillers indicating the presence of hindered path for solvents to diffuse into the polymer matrix. The better reinforcement at lower filler loading was confirmed from the cross-link density values and mechanical properties. The transport data obtained were applied to mathematical models for predicting the diffusion behaviour through nanocomposite membranes and to elucidate the physical mechanism of transport

Adding 6 months of androgen deprivation therapy to postoperative radiotherapy for prostate cancer: a comparison of short-course versus no androgen deprivation therapy in the RADICALS-HD randomised controlled trial

Background Previous evidence indicates that adjuvant, short-course androgen deprivation therapy (ADT) improves metastasis-free survival when given with primary radiotherapy for intermediate-risk and high-risk localised prostate cancer. However, the value of ADT with postoperative radiotherapy after radical prostatectomy is unclear. Methods RADICALS-HD was an international randomised controlled trial to test the efficacy of ADT used in combination with postoperative radiotherapy for prostate cancer. Key eligibility criteria were indication for radiotherapy after radical prostatectomy for prostate cancer, prostate-specific antigen less than 5 ng/mL, absence of metastatic disease, and written consent. Participants were randomly assigned (1:1) to radiotherapy alone (no ADT) or radiotherapy with 6 months of ADT (short-course ADT), using monthly subcutaneous gonadotropin-releasing hormone analogue injections, daily oral bicalutamide monotherapy 150 mg, or monthly subcutaneous degarelix. Randomisation was done centrally through minimisation with a random element, stratified by Gleason score, positive margins, radiotherapy timing, planned radiotherapy schedule, and planned type of ADT, in a computerised system. The allocated treatment was not masked. The primary outcome measure was metastasis-free survival, defined as distant metastasis arising from prostate cancer or death from any cause. Standard survival analysis methods were used, accounting for randomisation stratification factors. The trial had 80% power with two-sided α of 5% to detect an absolute increase in 10-year metastasis-free survival from 80% to 86% (hazard ratio [HR] 0·67). Analyses followed the intention-to-treat principle. The trial is registered with the ISRCTN registry, ISRCTN40814031, and ClinicalTrials.gov, NCT00541047. Findings Between Nov 22, 2007, and June 29, 2015, 1480 patients (median age 66 years [IQR 61–69]) were randomly assigned to receive no ADT (n=737) or short-course ADT (n=743) in addition to postoperative radiotherapy at 121 centres in Canada, Denmark, Ireland, and the UK. With a median follow-up of 9·0 years (IQR 7·1–10·1), metastasis-free survival events were reported for 268 participants (142 in the no ADT group and 126 in the short-course ADT group; HR 0·886 [95% CI 0·688–1·140], p=0·35). 10-year metastasis-free survival was 79·2% (95% CI 75·4–82·5) in the no ADT group and 80·4% (76·6–83·6) in the short-course ADT group. Toxicity of grade 3 or higher was reported for 121 (17%) of 737 participants in the no ADT group and 100 (14%) of 743 in the short-course ADT group (p=0·15), with no treatment-related deaths. Interpretation Metastatic disease is uncommon following postoperative bed radiotherapy after radical prostatectomy. Adding 6 months of ADT to this radiotherapy did not improve metastasis-free survival compared with no ADT. These findings do not support the use of short-course ADT with postoperative radiotherapy in this patient population

Duration of androgen deprivation therapy with postoperative radiotherapy for prostate cancer: a comparison of long-course versus short-course androgen deprivation therapy in the RADICALS-HD randomised trial

Background Previous evidence supports androgen deprivation therapy (ADT) with primary radiotherapy as initial treatment for intermediate-risk and high-risk localised prostate cancer. However, the use and optimal duration of ADT with postoperative radiotherapy after radical prostatectomy remains uncertain. Methods RADICALS-HD was a randomised controlled trial of ADT duration within the RADICALS protocol. Here, we report on the comparison of short-course versus long-course ADT. Key eligibility criteria were indication for radiotherapy after previous radical prostatectomy for prostate cancer, prostate-specific antigen less than 5 ng/mL, absence of metastatic disease, and written consent. Participants were randomly assigned (1:1) to add 6 months of ADT (short-course ADT) or 24 months of ADT (long-course ADT) to radiotherapy, using subcutaneous gonadotrophin-releasing hormone analogue (monthly in the short-course ADT group and 3-monthly in the long-course ADT group), daily oral bicalutamide monotherapy 150 mg, or monthly subcutaneous degarelix. Randomisation was done centrally through minimisation with a random element, stratified by Gleason score, positive margins, radiotherapy timing, planned radiotherapy schedule, and planned type of ADT, in a computerised system. The allocated treatment was not masked. The primary outcome measure was metastasis-free survival, defined as metastasis arising from prostate cancer or death from any cause. The comparison had more than 80% power with two-sided α of 5% to detect an absolute increase in 10-year metastasis-free survival from 75% to 81% (hazard ratio [HR] 0·72). Standard time-to-event analyses were used. Analyses followed intention-to-treat principle. The trial is registered with the ISRCTN registry, ISRCTN40814031, and ClinicalTrials.gov , NCT00541047 . Findings Between Jan 30, 2008, and July 7, 2015, 1523 patients (median age 65 years, IQR 60–69) were randomly assigned to receive short-course ADT (n=761) or long-course ADT (n=762) in addition to postoperative radiotherapy at 138 centres in Canada, Denmark, Ireland, and the UK. With a median follow-up of 8·9 years (7·0–10·0), 313 metastasis-free survival events were reported overall (174 in the short-course ADT group and 139 in the long-course ADT group; HR 0·773 [95% CI 0·612–0·975]; p=0·029). 10-year metastasis-free survival was 71·9% (95% CI 67·6–75·7) in the short-course ADT group and 78·1% (74·2–81·5) in the long-course ADT group. Toxicity of grade 3 or higher was reported for 105 (14%) of 753 participants in the short-course ADT group and 142 (19%) of 757 participants in the long-course ADT group (p=0·025), with no treatment-related deaths. Interpretation Compared with adding 6 months of ADT, adding 24 months of ADT improved metastasis-free survival in people receiving postoperative radiotherapy. For individuals who can accept the additional duration of adverse effects, long-course ADT should be offered with postoperative radiotherapy. Funding Cancer Research UK, UK Research and Innovation (formerly Medical Research Council), and Canadian Cancer Society

Gregory's common law forms, including declarations, pleas, replications, rejoinders, sur-rejoinders, summonses, writs, and entries

Includes bibliographical references and index.Mode of access: Internet

Novel phototransformation of O-nitrobenzylic polymers to azopolymers

Synthesis and phototransformations of a polymer bearing two O-nitrobenzylic chromophores at symmetrical positions per repeating unit to a polar photochromic azopolymer are described

Development and performance analysis of fluoroelastomer-graphite nanoplatelet nanocomposites

194-200Fluoroelastomer/graphite nanoplatelet (FKM/GNP) nanocomposites were prepared by two-roll mixing. The effect of graphite nanoplatelets on the mechanical and thermal properties of fluoroelastomer nanocomposites was studied as a function of filler loading. The dispersion and interaction of the filler in the polymer matrix was analyzed by scanning electron microscopy (SEM) and X-ray diffraction (XRD) analysis. It was found that the nanocomposite with 8 phr of filler loading showed optimum properties with 400% enhancement in tensile properties and 140% increase in tear strength. The thermal stability is also enhanced for 8 phr filler loaded fluoelastomer nanocomposite and only 32% weight loss was observed at 475°C. Incorporation of GNP efficiently improved both the thermal and mechanical properties of the nanocomposites by its interaction with the polymer matrix

Studies of Vapour Permeation of Chlorinated Hydrocarbons Through Natural Rubber-Clay Nanocomposite Membranes

Natural Rubber/ clay nanocomposite membranes were prepared by blending on a two-roll mill followed by compression moulding in a hydraulic press. Vapour permeation studies were conducted with various chlorinated hydrocarbons for the characterization of membrane. Special attention has been given to the effect of clay concentration, type of clay, size of penetrant and type of vulcanization on the vapour transport behaviour of composites. It was found that permeability is low at higher clay concentration and also the permeability coefficient decreases with increase in penetrant size. Peroxide vulcanized membrane exhibit lowest vapour permeability than conventionally and efficiently vulcanized membrane, which can be attributed to the higher crosslink density of peroxide vulcanized membranes. The effect of clay concentration on the sorption and diffusion behaviour of composites is also investigated