The structure of poly(9,9-dioctylfluorene-2,7-diyl) (PF8) in deuterated toluene solutions at concentrations ranging from 0.60% to 7.0% (w/v) has been investigated by means of small-angle neutron scattering (SANS) and nuclear magnetic resonance (NMR) spectroscopy. PF8 chains exhibited aggregation above 1.0%, where the corresponding SANS profiles were characterized by the superposition of an aggregate component and a dynamic component associated with the transient network formed by interchain overlap. The 1H NMR resonance lines for both the polymer as well as for the residual protons in the solvent showed large upfield shift at higher concentrations, indicating strong polymer−solvent interaction. At a higher concentration (4.5%) an additional resonance line was observed in the aromatic regions of both the 1H and the 2H spectra that has been attributed to a residual anisotropic chemical shift of the solvent molecules. The later phenomenon is suggestive of the existence of magnetically anisotropic aggregate domains of PF8 dispersed in an isotropic bulk.

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This study deals with the fabrication of composite matrix from saw dust (SD) and recycled polyethylene terephthalate (PET) at different ratio (w/w) by flat-pressed method. The wood plastic composites (WPCs) were made with a thickness of 6 mm after mixing the saw dust and PET in a rotary type blender followed by flat press process. Physical i.e., density, moisture content (MC), water absorption (WA) and thickness swelling (TS), and mechanical properties i.e., Modulus of Elasticity (MOE) and Modulus of Rupture (MOR) were assessed as a function of mixing ratios according to the ASTM D-1037 standard. WA and TS were measured after 24 hours of immersion in water at 25, 50 and 75°C temperature. It was found that density decreased 18.3% when SD content increased from 40% to 70% into the matix. WA and TS increased when the PET content decreased in the matrix and the testing water temperature increased. MOE and MOR were reached to maximum for the fabricated composites (2008.34 and 27.08 N/mm2, respectively) when the SD content were only 40%. The results indicated that the fabrication of WPCs from sawdust and PET would technically feasible; however, the use of additives like coupling agents could further enhance the properties of WPCs.

Segments of conjugated polymers display the propensity to aggregate in solutions with common organic solvents. Here we revealed that the segmental aggregation of a conjugated polymer, poly(9,9-bis(2-ethylhexyl)fluorene-2,7-diyl), (PF2/6), in toluene was stabilized by the polymer-solvent complex formation through pi-pi stacking induction of solvent molecules and polymer segments. In this case, a portion of the solvent was trapped inside the aggregate domains upon bringing the system to the subambient temperatures. The residence time of these associated solvent molecules became long enough to yield a separate upfield-shifted NMR resonance. The line-shape of this resonance revealed alignment of the polymer segments in the aggregates. A portion of the solvent was frozen in the compact structure due to the formation of strong polymer-solvent complex.

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Supramolecular comb-coil block copolymers formed by the stoichiometric complexation of two amphiphilic surfactants, dodecylbenzenesulfonic acid (DBSA) and 3-pentadecylphenol (PDP), with the poly(4-vinylpyridine) (P4VP) blocks in a linear PS-b-P4VP and a nonlinear A n B n -type heteroarm star PS-P4VP copolymer have been investigated. All linear and heteroarm star systems under study exhibited lamellae-within-lamellae morphology even at high PS volume fraction, at which the previously studied systems showed lamellae-within-cylinder or lamellae-within-sphere morphology. The interlamellar distances of the larger-scale copolymer microdomains were found to be much larger in all heteroarm complexes than those in their linear counterparts. This was attributed to the chain crowding effect coupled with the different types of arrangement of comb blocks forming the smaller-scale lamellar mesophase. Moreover, the order−disorder transition temperatures of both the larger- and smaller-scale structures in the heteroarm star systems were higher than those associated with the linear diblocks due to the lower entropy of transition.