scholarly journals Influence of Uncoupled Diblock Molecules on Mechanical Properties of Styerene/Butadiene/ Styrene Triblock Copolymers

2012 ◽  
Vol 12 ◽  
pp. 149-156 ◽  
Author(s):  
Rameshwar Adhikari
Keyword(s):  
Mechanical Properties ◽  
Block Copolymers ◽  
Tensile Deformation ◽  
Triblock Copolymers ◽  
Large Strain ◽  
Deformation Behaviour ◽  
Mechanical Analysis ◽  
Transmission Electron ◽  
Star Block Copolymers ◽  
Butadiene Styrene

The influence of the presence of uncoupled polystyrene-block-polybutadiene (SB) diblock chains to polystyrene-block-polybutadiene-block-polystyrene (SBS) triblock copolymers on the mechanical properties of the latter has been studied by means of tensile testing and dynamic mechanical analysis preparing several lamellae forming SBS/ SB blends through solution casting. The microphase-separated morphology of the samples was investigated by transmission electron microscopy. Both large strain deformation tensile deformation behaviour and viscoelastic properties of the SBS block copolymers were found to be affected appreciably by the presence of uncoupled SB diblock. The storage modulus of linear SBS was found to drop more sharply in the plateau region than for the radial SBS at the same SB content. At low SB content (up to 20 wt.-% for linear SBS and still higher for radial one), the overall tensile properties was not negatively influenced. On the whole, star block copolymers were found to be less sensitive towards the presence of diblock.DOI: http://dx.doi.org/10.3126/njst.v12i0.6493 Nepal Journal of Science and Technology 12 (2011) 149-156

Rheology of Block Copolymers

2007 ◽  
Author(s):  
Chang Dae Han
Keyword(s):  
Mechanical Properties ◽  
Molecular Weight ◽  
Block Copolymers ◽  
Small Angle ◽  
Volume Fraction ◽  
Synthesis Methods ◽  
Chemical Structures ◽  
X Ray Scattering ◽  
Transmission Electron ◽  
Molecular Weight Form

Block copolymer consists of two or more long blocks with dissimilar chemical structures which are chemically connected. There are different architectures of block copolymers, namely, AB-type diblock, ABA-type triblock, ABC-type triblock, and AmBn radial or star-shaped block copolymers, as shown schematically in Figure 8.1. The majority of block copolymers has long been synthesized by sequential anionic polymerization, which gives rise to narrow molecular weight distribution, although other synthesis methods (e.g., cationic polymerization, atom transfer radical polymerization) have also been developed in the more recent past. Owing to immiscibility between the constituent blocks, block copolymers above a certain threshold molecular weight form microdomains (10–50 nm in size), the structure of which depends primarily on block composition (or block length ratio). The presence of microdomains confers unique mechanical properties to block copolymers. There are many papers that have dealt with the synthesis and physical/mechanical properties of block copolymers, too many to cite them all here. There are monographs describing the synthesis and physical properties of block copolymers (Aggarwal 1970; Burke and Weiss 1973; Hamley 1998; Holden et al. 1996; Hsieh and Quirk 1996; Noshay and McGrath 1977). Figure 8.2 shows schematically four types of equilibrium microdomain structures observed in block copolymers. Referring to Figure 8.2, it is well established (Helfand and Wasserman 1982; Leibler 1980) that in microphase-separated block copolymers, spherical microdomains are observed when the volume fraction f of one of the blocks is less than approximately 0.15, hexagonally packed cylindrical microdomains are observed when the value of f is between approximately 0.15 and 0.44, and lamellar microdomains are observed when the value of f is between approximately 0.44 and 0.50. Some investigators have observed ordered bicontinuous double-diamonds (OBDD) (Thomas et al. 1986; Hasegawa et al. 1987) or bicontinuous gyroids (Hajduk et al. 1994) at a very narrow range of f (say, between approximately 0.35 and 0.40) for certain block copolymers. Figure 8.2 shows only one half of the symmetricity about f = 0.5. Transmission electron microscopy (TEM), small-angle X-ray scattering (SAXS), and small-angle neutron scattering (SANS) have long been used to investigate the types of microdomain structures in block copolymers.

Flow Behavior of Composites of PA6/Kaolin Nanoparticles

2014 ◽  
Vol 703 ◽  
pp. 45-50
Author(s):  
Chao Wang ◽  
Ying Chun Li ◽  
Guo Sheng Hu
Keyword(s):  
Mechanical Properties ◽  
Flow Behavior ◽  
Acrylonitrile Butadiene Styrene ◽  
Nylon 6 ◽  
Mechanical Analysis ◽  
Melt Blending ◽  
Styrene Maleic Anhydride ◽  
The Impact ◽  
Scanning Electron ◽  
Butadiene Styrene

The blends of Nylon 6/Acrylonitrile-Butadiene-Styrene (ABS) with styrene-maleic anhydride (SMA) was prepared by melt blending as the compatilizer. Mechanical properties, dynamic mechanical analysis (DMA) and fracture appearances were determined. It was found that the impact and tensile strength firstly increased and then decreased along with the increase of the SMA content. The properties reached maximum values when the content of SMA was 1.5%. The results of DMA and scanning electron microscope (SEM) indicated that the addition of SMA can effectively enhance the compatibility of Nylon 6 and ABS. Key words: Nylon 6, ABS, SMA, blends, modification

scholarly journals Enhancement of Mechanical and Thermal Properties of Polylactic Acid/Polycaprolactone Blends by Hydrophilic Nanoclay

2013 ◽  
Vol 2013 ◽  
pp. 1-11 ◽  
Author(s):  
Chern Chiet Eng ◽  
Nor Azowa Ibrahim ◽  
Norhazlin Zainuddin ◽  
Hidayah Ariffin ◽  
Wan Md. Zin Wan Yunus ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Polylactic Acid ◽  
Mechanical Analysis ◽  
Basal Spacing ◽  
Mechanical And Thermal Properties ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
The Matrix ◽  
Thermal Stability Of

The effects of hydrophilic nanoclay, Nanomer PGV, on mechanical properties of Polylactic Acid (PLA)/Polycaprolactone (PCL) blends were investigated and compared with hydrophobic clay, Montmorillonite K10. The PLA/PCL/clay composites were prepared by melt intercalation technique and the composites were characterized by X-ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), Thermogravimetric Analysis (TGA), Dynamic Mechanical Analysis (DMA), Scanning Electron Microscopy (SEM), and Transmission Electron Microscopy (TEM). FTIR spectra indicated that formation of hydrogen bond between hydrophilic clay with the matrix. XRD results show that shifting of basal spacing when clay incorporated into polymer matrix. TEM micrographs reveal the formation of agglomerate in the composites. Based on mechanical properties results, addition of clay Nanomer PGV significantly enhances the flexibility of PLA/PCL blends about 136.26%. TGA showed that the presence of clay improve thermal stability of blends. DMA show the addition of clay increase storage modulus and the presence of clay Nanomer PGV slightly shift two Tg of blends become closer suggest that the presence of clay slightly compatibilizer the PLA/PCL blends. SEM micrographs revealed that presence of Nanomer PGV in blends influence the miscibility of the blends. The PLA/PCL blends become more homogeneous and consist of single phase morphology.

Mechanical properties and morphology of polypropylene/poly(acrylonitrile–butadiene–styrene) nanocomposites

2016 ◽  
Vol 49 (3) ◽  
pp. 209-225 ◽  
Author(s):  
Mohamad Al Hafiz Ibrahim ◽  
Azman Hassan ◽  
Mat Uzir Wahit ◽  
Mahbub Hasan ◽  
Munirah Mokhtar
Keyword(s):  
Mechanical Properties ◽  
Maleic Anhydride ◽  
Acrylonitrile Butadiene Styrene ◽  
Impact Testing ◽  
Silicate Layer ◽  
Scanning Electron Micrographs ◽  
Electron Microscopic ◽  
Transmission Electron ◽  
Poly Acrylonitrile ◽  
Butadiene Styrene

Polypropylene (PP)/poly(acrylonitrile–butadiene–styrene) (ABS) blends containing montmorillonite (MMT) compatibilized with polypropylene-grafted maleic anhydride were prepared by melt extrusion using twin screw extruder followed by injection molding. Mechanical properties were evaluated through tensile, flexural, and impact testing. The microstructure and formation of nanocomposites were assessed by scanning and transmission electron microscopy and X-ray diffraction (XRD). Incorporation of polypropylene-grafted maleic anhydride and MMT into PP/ABS blend led to higher strength and stiffness but at the expense of toughness. Scanning electron micrographs revealed a fine and homogeneous dispersion of ABS phase in PP matrix. Both XRD and transmission electron microscopic analysis revealed the formation of intercalated clay silicate layer in PP/ABS nanocomposites.

Superlattices in block copolymer blends with attractive interactions

e-Polymers ◽  
2001 ◽  
Vol 1 (1) ◽  
Author(s):  
Kirsten Markgraf ◽  
Volker Abetz
Keyword(s):  
Electron Microscopy ◽  
Triblock Copolymer ◽  
Diblock Copolymers ◽  
Triblock Copolymers ◽  
Mechanical Analysis ◽  
Butyl Methacrylate ◽  
Mixed Solution ◽  
Copolymer Blends ◽  
Transmission Electron ◽  
Cyclohexyl Methacrylate

AbstractBlends of microphase separated polystyrene-block-polybutadiene-blockpoly( methacrylic acid) triblock copolymers (SBA) with polystyrene-block-poly(2- vinylpyridine) (SV) or poly(2-vinylpyridine)-block-poly(cyclohexyl methacrylate) (VC) diblock copolymers were prepared and characterized. Attractive segmental interactions through hydrogen bonds between A and V could be monitored by infrared spectroscopy and dynamic mechanical analysis. Common superlattices were obtained by casting from a mixed solution of these block copolymers in tetrahydrofuran and were investigated by transmission electron microscopy. Varying the amount of hydrogen bonding donors via controlled saponification of an SBT triblock copolymer (T: poly(tert-butyl methacrylate)) lead to different superlattices in blends with a VC diblock copolymer.

ENGINEERING ORIENTATION IN BLOCK COPOLYMERS FOR APPLICATION TO PROSTHETIC HEART VALVES

2010 ◽  
Vol 03 (04) ◽  
pp. 249-252 ◽  
Author(s):  
JOANNA STASIAK ◽  
GEOFF D. MOGGRIDGE ◽  
ADRIANO ZAFFORA ◽  
ANNA PANDOLFI ◽  
MARIA L. COSTANTINO
Keyword(s):  
Mechanical Properties ◽  
Block Copolymer ◽  
Block Copolymers ◽  
Long Range ◽  
Heart Valves ◽  
Mechanical Response ◽  
Mechanical Performance ◽  
Prosthetic Heart Valves ◽  
Anisotropic Mechanical Properties ◽  
Butadiene Styrene

This study demonstrates how the mechanical performance of polymeric material can be enhanced by morphology and phase orientation of block copolymers to achieve desired anisotropic mechanical properties. The material used was a new Kraton block copolymer consisting of styrene-isoprene-butadiene-styrene blocks having cylindrical morphology. We report a method of achieving long range uniaxial as well as biaxial orientation of block copolymer. Each microstructural organization results in a specific mechanical performance, which depends on the direction of the applied deformation. The method of tailoring mechanical properties by engineering microstructure may be successfully utilized to applications requiring anisotropic mechanical response, such as prosthetic heart valves.

Effects of organoclay on morphology and mechanical properties in acrylonitrile-butadiene-styrene/polyamide 6/ organoclay ternary nanocomposites

e-Polymers ◽  
2012 ◽  
Vol 12 (1) ◽  
Author(s):  
Wei Yan ◽  
Shuhao Qin ◽  
Jianbing Guo, ◽  
Min He ◽  
Minmin Zhang ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Domain Size ◽  
Acrylonitrile Butadiene Styrene ◽  
Polyamide 6 ◽  
X Ray Diffraction ◽  
Melt Mixing ◽  
Transmission Electron ◽  
Morphology And Mechanical Properties ◽  
Butadiene Styrene

AbstractIn this article, polyamide 6(PA6)/organoclay masterbatch were prepared by melt mixing, and then acrylonitrile-butadiene-styrene(ABS)/polyamide 6(PA6)(70/30,w/w) nanocomposites were prepared by the melt mixing of PA6, ABS and organoclay. The effect of organoclay platelets on morphology and mechanical properties of ABS/PA6/organoclay ternary nanocomposites had been investigated by wide angle X-ray diffraction (WAXD) and transmission electron microscopy (TEM), scanning electron microscopy (SEM) and mechanical properties testing. Morphology analysis revealed that organoclay platelets were selectively dispersed and exfoliated in PA6 phase, but some were located in interface of PA6 and ABS phase. The droplet size of PA6 dispersed phase were gradually reduced less than 4 phr organoclay, then the dispersed domain size became unchanged with the addition of various organoclay. It suggested the organoclay can compatibilize the ABS/PA6 blend nanocomposite. Moreover, the flexural strength and modulus increase with increasing organoclay content, but the tensile strength became maximal at 3 phr organoclay. The organoclay has no effect on impact strength of ABS/PA6 blend nanocomposite.

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