scholarly journals In Situ Modification of Polyisoprene by Organo-Nanoclay during Emulsion Polymerization for Reinforcing Natural Rubber Thin Films

Polymers ◽  
2019 ◽  
Vol 11 (8) ◽  
pp. 1338
Author(s):  
Jadsadaporn Chouytan ◽  
Ekwipoo Kalkornsurapranee ◽  
Christopher Fellows ◽  
Wisut Kaewsakul
Keyword(s):  
Thin Films ◽  
Natural Rubber ◽  
Emulsion Polymerization ◽  
Sodium Dodecyl ◽  
Polymer Particle ◽  
Nanocomposite Films ◽  
Polymer Particles ◽  
Scanning Calorimetry ◽  
In Situ Modification ◽  
Monomer Content

Nanoclay-modified polyisoprene latexes were prepared and then used as a reinforcing component in natural rubber (NR) thin films. Starve-fed emulsion (SFE) polymerization gives a higher conversion than the batch emulsion (BE), while the gel and coagulation contents from both systems are comparable. This is attributed to the SFE that provides a smaller average polymer particle size which in turn results in a greater polymerization locus, promoting the reaction rate. The addition of organo-nanoclay during synthesizing polyisoprene significantly lessens the polymerization efficiency because the nanoclay has a potential to suppress nucleation process of the reaction. It also intervenes the stabilizing efficiency of the surfactant—SDS or sodium dodecyl sulfate, giving enlarged average sizes of the polymer particles suspended in the latexes. TEM images show that nanoclay particles are attached on and/or inserted in the polymer particles. XRD and thermal (differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA)) analyses were employed to assess the d-spacing of nanoclay structure in NR nanocomposite films, respectively. Based on the overall results, 5 wt% of nanoclay relative to the monomer content utilized to alter the polyisoprene during emulsion polymerization is an optimum amount since the silicate plates of nanoclay in the composite exhibit the largest d-spacing which maximizes the extent of immobilized polymer constituent, giving the highest mechanical properties to the films. The excessive amounts of nanoclay used, i.e., 7 and 10 wt% relative to the monomer content, reduce the reinforcing power because of the re-agglomeration effect.

Synthesis of n-octadecane/poly (styrene-methyl methacrylate) (St-MMA) energy-storage microcapsules via emulsion polymerization

2017 ◽  
Vol 31 (11) ◽  
pp. 1443-1454
Author(s):  
Weili Wu ◽  
Zhe Chen
Keyword(s):  
Particle Size ◽  
Energy Storage ◽  
Methyl Methacrylate ◽  
Phase Change ◽  
Emulsion Polymerization ◽  
Sodium Dodecyl ◽  
Sodium Dodecyl Benzene Sulfonate ◽  
Scanning Calorimetry ◽  
Transmission Electron ◽  
Size Dispersion

Poly (methyl methacrylate) block copolymer is interesting due to its good compatibility with many polymers. In this study, a novel phase-change energy storage material, n-octadecane/poly (styrene-methyl methacrylate) (OD/P(St-MMA)) microcapsules, were designed and synthesized by emulsion polymerization, in which n-OD was used as core materials, the copolymer of St and MMA as shell materials, and sodium dodecyl benzene sulfonate (SDBS) as emulsifier. The morphology, phase-change thermal properties and thermal stability of microcapsules were investigated by particle size analyzer, transmission electron microscope, thermogravimetric (TG) analyzer, and differential scanning calorimetry (DSC). The results showed that when the ratio of the two monomers, St and MMA, was 1/5 and the dosage of SDBS was 1.5 g (3% of the total mass), the particle size dispersion of microcapsules was uniform and microcapsule particles were well wrapped. TG analysis showed that the long-term use temperature of microcapsules could not exceed 131°C. DSC showed that the phase-change enthalpy of microcapsule was 148.39 J·g−1, which indicated the microcapsules had excellent energy storage property.

SYNTHESIS AND CHARACTERIZATION OF POLY(BUTYL ACRYLATE-CO-METHYL METHACRYLATE)/CLAY NANOCOMPOSITES VIA EMULSION POLYMERIZATION

2006 ◽  
Vol 05 (02n03) ◽  
pp. 291-297 ◽  
Author(s):  
ZHIYI ZHANG ◽  
NING ZHAO ◽  
WEI WEI ◽  
DONG WU ◽  
YUHAN SUN
Keyword(s):  
Methyl Methacrylate ◽  
Emulsion Polymerization ◽  
Butyl Acrylate ◽  
Sodium Dodecyl ◽  
Sodium Dodecyl Benzene Sulfonate ◽  
Clay Nanocomposites ◽  
Scanning Calorimetry ◽  
Transmission Electron ◽  
Dodecyl Benzene Sulfonate ◽  
Clay Layers

Poly(butyl acrylate-co-methyl methacrylate)/clay nanocomposites were synthesized via emulsion polymerization with an emulsifier (sodium dodecyl benzene sulfonate, SDBS), an initiator (ammonium persulate, APS), acrylic acid ester monomer and Na -montmorillonite. It was found that the addition of SDBS and water widened the gap between clay layers and facilitated monomers to penetrate into clay. Through initiator, comonomers were polymerized in the montmorillonite galleries. The structure of extracted nanocomposites was confirmed by XRD, transmission electron microscopy (TEM). Their thermal property and molecule weight were investigated by differential scanning calorimetry (DSC) and gel-penetrate chromatogram (GPC).

Nanomechanical Properties of UV Degraded TiO2/Epoxy Nanocomposites

2004 ◽  
Vol 841 ◽  
Author(s):  
Stephanie Scierka ◽  
Peter L. Drzal ◽  
Amanda L. Forster ◽  
Stephanie Svetlik
Keyword(s):  
Thin Films ◽  
Volume Fraction ◽  
Surface Region ◽  
Chemical Oxidation ◽  
Nanocomposite Films ◽  
Attenuated Total Reflectance ◽  
Integrating Sphere ◽  
Scanning Calorimetry ◽  
Nanocomposite Thin Films ◽  
Instrumental Indentation

ABSTRACTModel epoxy nanocomposite thin films containing one of three types of titanium dioxide (TiO2) particles were degraded using an integrating sphere-based ultraviolet weathering chamber. Instrumental Indentation Testing (IIT) was used to measure nanomechanical changes in the surface region of thin films resulting from UV exposure. Attenuated Total Reflectance-Fourier Transform Infrared Spectroscopy (ATR-FTIR) and Differential Scanning Calorimetry (DSC) were used to support the mechanical results with chemical and thermal data. The unfilled epoxy was the most photosensitive sample tested, exhibiting the highest rates of chemical oxidation, the largest decrease in the glass transition (Tg), and the greatest increase in elastic modulus with increased exposure. Similar trends were observed in the nanocomposite films, but the rates of change were much lower than the unfilled epoxy and decreased with increasing volume fraction of nanoparticles.

scholarly journals Effect of tungsten disulfide nanotubes on crystallization of polylactide under uniaxial deformation and annealing

2021 ◽  
Vol 2 (1) ◽  
Author(s):  
Fausta Loffredo ◽  
Loredana Tammaro ◽  
Tiziana Di Luccio ◽  
Carmela Borriello ◽  
Fulvia Villani ◽  
...  
Keyword(s):  
Biomedical Applications ◽  
Structural Evolution ◽  
Tungsten Disulfide ◽  
Fine Tuning ◽  
Nanocomposite Films ◽  
Uniaxial Deformation ◽  
Scanning Calorimetry ◽  
X Ray ◽  
X Ray Scattering

AbstractTungsten disulfide (WS2) nanotubes (NTs) are examined here as a filler for polylactide (PLA) for their ability to accelerate PLA crystallization and for their promising biocompatibility in relevant to biomedical applications of PLA-WS2 nanocomposites. In this work, we have studied the structural and thermal properties of PLA-WS2 nanocomposite films varying the concentration of WS2 NTs from 0 (neat PLA) to 0.6 wt%. The films were uniaxially drawn at 90 °C and annealed at the same temperature for 3 and 10 min. Using wide angle x-ray scattering, Raman spectroscopy and differential scanning calorimetry, we probed the effects of WS2 NT addition on the structure of the PLA films at various stages of processing (unstretched, stretching, annealing). We found that 0.6 wt% of WS2 induces the same level of crystallinity in as stretched PLA-WS2 as annealing in neat PLA for 10 min. These data provide useful insights into the role of WS2 NTs on the structural evolution of PLA-WS2 composites under uniaxial deformation, and extend their applicability to situations where fine tuning of PLA crystallinity is desirable.

Enhanced electrical conductivity of Au–LaNiO3 nanocomposite thin films by chemical solution deposition

RSC Advances ◽  
2015 ◽  
Vol 5 (94) ◽  
pp. 76783-76787 ◽  
Author(s):  
H. L. Wang ◽  
X. K. Ning ◽  
Z. J. Wang
Keyword(s):  
Thin Films ◽  
Electrical Conductivity ◽  
Electrical Properties ◽  
Chemical Solution Deposition ◽  
Nanocomposite Films ◽  
Chemical Solution ◽  
Solution Deposition ◽  
Nanocomposite Thin Films ◽  
One Step

Au–LaNiO3 (Au–LNO) nanocomposite films with 3.84 at% Au were firstly fabricated by one-step chemical solution deposition (CSD), and their electrical properties were investigated.

Surfactant Treatment and Leaching Combination Process for Preparation of Deproteinized Natural Rubber Latex

2015 ◽  
Vol 659 ◽  
pp. 500-504
Author(s):  
Jirapornchai Suksaeree ◽  
Wirach Taweepreda ◽  
Wiwat Pichayakorn
Keyword(s):  
Natural Rubber ◽  
Skin Irritation ◽  
Sodium Dodecyl ◽  
Natural Rubber Latex ◽  
Rubber Latex ◽  
Combination Process ◽  
Surfactant Treatment ◽  
Leaching Process ◽  
Sodium Lauryl Ether Sulfate ◽  
Cocamidopropyl Betaine

This study aimed to improve the efficacy of protein removal from fresh natural rubber latex (NRL) and to decrease the production cost by using surfactant treatment and leaching combination processes. The 0.5-3% anionic surfactants, i.e. sodium dodecyl sulfate or sodium lauryl ether sulfate, nonionic tween80 surfactant, or an amphoteric cocamidopropyl betaine surfactant was used in surfactant treatment process. Moreover, water, aqueous surfactant solutions, and/or 1-5% organic solvents (i.e. ethanol, isopropanol and/or acetone) was then used in leaching process. The fresh NRL was preserved by paraben compounds in the presence of surfactant at ambient temperature for 20-120 minutes, and then centrifuged. This might prevent the skin irritation of deproteinized NRL (DNRL) caused by ammonium stabilizer that normally uses in latex industry. The upper rubber mass was then leached for upto three cycles with leaching solvents, and then finally redispersed in distilled water. The milky-like DNRLs were obtained by these processes. Their dry rubber contents were 41-47% that could be adjusted. Their viscosities were 9-13 centipoises with the pH of 6.04-6.61. The protein residues in these DNRLs were 0.0000-0.3244% which were lower than that of fresh NRL (1.2428%). These indicated the efficacy of studied deproteinization process for 73.90-100.0%. Types and concentrations of surfactant, incubation times, leaching solvents, and cycles of leaching process affected the efficacy of deproteinization process. Moreover, the properties of these dried films were not different from that of fresh NR film. This DNRL could be further used for several applications including medical skin products.

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