Sea-island structure

Figure 12.6a andb shows AFM images of PS-h-P4VP (301 000 19600) films before and after doping of TCPP, respectively. The regular sea-island structure with... 

Figure 12.6 AFM images of thin PS-fo-P4VP (301 000 19 600) films with sea-island structures (sea parts of PS components and island parts of P4VP components) on glass substrates, and height profiles of horizontal lines in these images, (a) Before and (b) after being doped with TCPP. Doped films irradiated using one shot with fluences of about (c) 110 and (d) 150 mj cm in methanol. Height profiles of...

Wang, Z., Masuo, S., Machida, S. and Itaya, A. (2005) Application of dopant-induced laser ablation to site-selective modification of sea-island structures of polystyrene-fclock-poly(4-vinylpyridine) films. Jpn. J. Appl. Phys., 44, L402-L404. 

When a modified natural rubber is compounded, an amount of a modified natural rubber is preferably more than 30% by weight in order to obtain significant effect of improvement in grip performance. On the other hand, an amount of a modified natural rabber is preferably 15-85% by weight when used for a sidewall in order to allow the formation of an appropriate sea-island structure with other rabber as NR, and thereby improve crack resistance properly of the tire compound. 

Scanning electron microscopy (SEM) is one of the very useful microscopic methods for the morphological and structural analysis of materials. Larena et al. classified nanopolymers into three groups (1) self-assembled nanostructures (lamellar, lamellar-within-spherical, lamellar-within-cylinder, lamellar-within-lamellar, cylinder within-lamellar, spherical-within-lamellar, and colloidal particles with block copolymers), (2) non-self-assembled nanostructures (dendrimers, hyperbranched polymers, polymer brushes, nanofibers, nanotubes, nanoparticles, nanospheres, nanocapsules, porous materials, and nano-objects), and (3) number of nanoscale dimensions [uD 1 nD (thin films), 2 nD (nanofibers, nanotubes, nanostructures on polymeric surfaces), and 3 nD (nanospheres, nanocapsules, dendrimers, hyperbranched polymers, self-assembled structures, porous materials, nano-objects)] [153]. Most of the polymer blends are immiscible, thermodynamically incompatible, and exhibit multiphase structures depending on the composition and viscosity ratio. They have two types of phase morphology sea-island structure (one phase are dispersed in the matrix in the form of isolated droplets, rods, or platelets) and co-continuous structure (usually formed in dual blends). 

Figure 30 shows a transmission electron micrograph of a thin film prq>ared from an AcOEt solution of part B in run 1. A sea island structure is clearly observed. The occurrence of such a microphase separation supports the conclusion that this polymer is a block copolymer. 

Sumiploy SK1800 and SK1660 have a sea-island structures where PES is dispersed as particles in PEEK matrix. Sumiploy EK1400 has reinforced structure because liquid crystalline pol3mier is oriented as reinforcing fibres in PEEK matrix. 

Upon dry spinning this solution in heated air, a fiber with a sea island structure is formed. After spinning, the fiber that has been stretched and heat treated is washed by water. Additives with poor molecular orientation are dissolved and removed, leaving a superfine fiber that consists of completely saponified PVA. When observed by an electron microscope, prior to microfibrilation the fiber has a diameter of approximately 20 pm, which then is reduced to submicrometers, thereby achieving sufficient microfibrilation [4]. 

Pre-reaction This can introduce sea-island structures in cured adhesive, and useful to reinforce adhesive layers. The technique has been applied to structural adhesives already. 

Further modification of the above nanostructures is useful for obtaining new functional materials. Thirdly, we apply the dopant-induced laser ablation technique to site-selectively doped thin diblock copolymer films with spheres (sea-island), cylinders (hole-network), and wormlike structures on the nanoscale [19, 20]. When the dye-doped component parts are ablated away by laser light, the films are modified selectively. Concerning the laser ablation of diblock copolymer films, Lengl et al. carried out the excimer laser ablation of diblock copolymer monolayer films, forming spherical micelles loaded with an Au salt to obtain metallic Au nanodots [21]. They used the laser ablation to remove the polymer matrix. In our experiment, however, the laser ablation is used to remove one component of block copolymers. Thereby, we can expect to obtain new functional materials with novel nanostmctures. 

Position-Selective Arrangement of Nanosize Polymer Microspheres Onto a PS-b-P4VP Diblock Copolymer Film with Nanoscale Sea-island Microphase Structure... 

Figure 12.1 AFM images of a PS-b-P4VP (301 000 19600) film (a) before and (b) after immersion in methanol for 75 min and the height profiles. S. Machida, H. Nakata, K. Yamada, A. Itaya Position-selective arrangement of nanosized polymer microsphere on diblock copolymer film with sea-island microphase structure.Jpn. /. Appl. Phys. 2006, 45, 4270—4273. Copyright Wiley InterScience. Reproduced with permission.

The solvent-etched fracture surface of folly cured PEI modified epoxy with different composition is shown in Figure 3.8. For PEI content smaller than 10wt%, the PEI-rich phase is dispersed in a continuous epoxy-rich matrix [i.e., sea-island morphology is observed (a and b)]. Above 25 wt% PEI content, nodular structure was observed (e and f) where the epoxy-rich phase forms spherical nodules and the PEI rich phase forms the matrix. With PEI content between 15 wt% and 20 wt%, dual phase morphology, where sea-island morphology and epoxy nodular structure coexist, is present (c and d). Similar morphology was observed in PEI/BPACY blend [47],... 

Ho et al (1996) examined polyol or polysiloxane thermoplastic polyurethanes (TPUs) as modifiers in cresol-formaldehye novolac epoxy resins cured with phenolic novolac resin for computer-chip encapsulation. A stable sea-island dispersion of TPU particles was achieved by the epoxy ring-opening with isocyanate groups of the urethane prepolymer to form an oxazolidone. The flexural modulus was reduced by addition of TPU and also the Tg was increased due to the rigid oxazolidone structure. Mayadunne et al (1999) extended this work to a series of phenol- and naphthol-based aralkyl epoxy resins. 

Immiscible polymer blends normally have a sea-island stmcture, where one polymer is dispersed as (normally spherical) particles in the other polymer, which forms the matrix, or a co-continuous structure, where both polymers are equally distributed in the blend without one polymer forming a continuous phase. For the blends to have good mechanical properties, it is also important that there is good interaction between the different components in the blend. To ensure this, researchers have tried a variety of methods to compatibilize the polymers in blends. The most used method is to add a third polymer, which interacts well with the other two polymers, into the blend. Reactive blending is another well-used method, and recently, a lot of investigation went into the use of (especially clay) nanoparticles to improve the interaction between the polymer components by locating themselves on the interfaces between the polymers. 

Modeled after a structure of collagen fiber bundles in a cow leather, a sea -island is made, and its micro fibers are bundled through extracting its sea component, and then they are made into non-woven fabrics, which ultimately turn man-made leathers through following processes. 

Cotton has a ribbon-like cross section with a hollow spiral twist structure (Fig. 2.3), dimensions ranging from superfine Sea Island cottons, with a length of 5 cm and a... 

NTS/FOETS) mixed monolayer showed phase-separated structure like sea-island, whose domain and matrix phases were composed of crystalline NTS and amorphous FOETS molecules, respectively. The (NTSQQQ /FOETS) mixed monolayer with the hydrophilic domain and the hydrophobic matrix was obtained by selective oxidization of the NTS phase in the (NTS/FOETS) mixed monolayer. Furthermore, the local height control on the NTScqoh phase of the (NTS ooh/P S) mixed monolayer was performed by chemisorption of NTS from the solution. The height increase in the NTScqoh phase was confirmed by AFM and lateral force microscopy (LFM). 

Rico et al. have observed the influence of some of these variables on the epoxy/polyester blends morphology. Three different structures can be formed depending on modifier concentration, sea-island, dual-structure and nodular morphology. The former was observed to show a low modifier amount (until 6% in this case), the dual-structure to show intermediate amounts (9-12%) and the latter to show modifier amounts of up to 15%. 

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