Effect of polymer–particle interaction on the fracture toughness of silica filled hydrogels

Soft Matter ◽  
2011 ◽  
Vol 7 (14) ◽  
pp. 6578 ◽  
Author(s):  
Wei-Chun Lin ◽  
Alba Marcellan ◽  
Dominique Hourdet ◽  
Costantino Creton
Polymers ◽  
2021 ◽  
Vol 13 (19) ◽  
pp. 3349
Author(s):  
Johannes Benz ◽  
Christian Bonten

Above a percolation threshold a flow restriction has to be overcome by higher pressure in plastic processing. Besides amount and geometry of fillers, the interactions of polymer and filler are important. By differing the amorphous phase of polymers into a rigid amorphous and a mobile amorphous fraction, predictions about interactions are possible. The objective is the generation of a flow restriction and the combined investigation of polymer–particle interaction. SiO2 was used up to 50 vol.% in different spherical sizes in PLA and PP. A capillary-rheometer was used as a tool to create a yield point and by that investigations into the state of the flow restriction were possible. All produced compounds showed, in plate-plate rheometry, an increase in viscosity for lower shear rates and a significant change in the storage modulus. In DSC, hardly any specific rigid amorphous fraction was detectable, which suggests that there is a minor interaction between macromolecules and filler. This leads to the conclusion that the change in flow behavior is mainly caused by a direct interaction between the particles, even though they are theoretically too far away from each other. First images in the state of the yield point show a displacement of the particles against each other.


1993 ◽  
Vol 304 ◽  
Author(s):  
Connie S. Heck ◽  
J. E. Roberts

AbstractThe adsorption behavior of model associative polymers in aqueous titanium dioxide (TiO2) and polystyrene latex (PS) particle dispersions has been studied using liquid-state Nuclear Magnetic Resonance (NMR) and a modified serum replacement technique (SRT). The structure of the associative polymer is a linear, water soluble, A-B-A block copolymer with a polyethylene oxide backbone and hydroxyl (H) or hexadecyl (C16H33) endgroups.Absolute intensity NMR measurements allow the determination of the adsorbed polymer configuration at the solid-solution interface and adsorption isotherms for comparison to the SRT results. Both the SRT and NMR results demonstrate that the adsorption/desorption of the C16 and H polymers is strongly affected by the substrate. For the polymer/PS particle systems, there is good agreement in complete surface saturation values for the SRT and NMR methods. In the polymer/TiO2 systems, the H polymer plateau as determined by NMR differs slightly from that determined by SRT. For the C16/TiO2 system the interpretation is less straightforward. Either the NMR saturation value is at least double that of the SRT value or the C16 and H polymers have very similar isotherms by NMR. This would suggest that on TiO2 the effect of the hydrophobe is minimal. For all the polymers the polymer/particle interaction on PS is strong and desorption is difficult while on TiO2 it is weak and completely reversible. A pancake-to-brush conformation change on the PS surface is evident for the C16 polymers and probably for the H polymer as well. The H polymer seems to form a multi-layered structure on PS from the NMR and laser light scattering results. The contribution of the hydrophobe and the effect of increasing the backbone molecular weight are clearly illustrated.


2019 ◽  
Vol 52 (22) ◽  
pp. 8741-8750
Author(s):  
Bradley W. Mansel ◽  
Chun-Yu Chen ◽  
Jhih-Min Lin ◽  
Yu-Shan Huang ◽  
Yu-Chiao Lin ◽  
...  

2020 ◽  
Vol 10 (11) ◽  
pp. 3688 ◽  
Author(s):  
Diego Lascano ◽  
Daniel Garcia-Garcia ◽  
Sandra Rojas-Lema ◽  
Luis Quiles-Carrillo ◽  
Rafael Balart ◽  
...  

In the present work, green-composites from a partially biobased epoxy resin (BioEP) reinforced with lignocellulosic particles, obtained from flax industry by-products or wastes, have been manufactured by casting. In this study, the flaxseed has been crushed by two different mechanical milling processes to achieve different particle sizes, namely coarse size (CFF), and fine size (FFF) particle flaxseed flour, with a particle size ranging between 100–220 µm and 40–140 µm respectively. Subsequently, different loadings of each particle size (10, 20, 30, and 40 wt%) were mixed with the BioEP resin and poured into a mold and subjected to a curing cycle to obtain solid samples for mechanical, thermal, water absorption, and morphological characterization. The main aim of this research was to study the effect of the particle size and its content on the overall properties of composites with BioEP. The results show that the best mechanical properties were obtained for composites with a low reinforcement content (10 wt%) and with the finest particle size (FFF) due to a better dispersion into the matrix, and a better polymer-particle interaction too. This also resulted in a lower water absorption capacity due to the presence of fewer voids in the developed composites. Therefore, this study shows the feasibility of using flax wastes from the seeds as a filler in highly environmentally friendly composites with a wood-like appearance with potential use in furniture or automotive sectors.


1996 ◽  
Vol 11 (7) ◽  
pp. 1739-1747 ◽  
Author(s):  
L. S. Tan ◽  
A. J. McHugh ◽  
M. A. Gülgün ◽  
W. M. Kriven

Microstructure, microchemistry and mechanical properties of hardened macro-defect-free (MDF) composites processed at various rotor rates in a Banbury mixer were investigated. A quiescently formed calcium aluminate-polyvinyl alcohol composite served as a substitute for an unmixed system. Results from the Banbury studies in conjunction with microchemical analysis of the unmixed composite showed evidence that the polymer-particle interaction is a mechanically induced crosslinking reaction. The rate of the mechano-chemistry increases with mixing speeds. Scanning electron micrographs (SEM) and transmission electron micrographs (TEM) of hardened composites mixed for 15 min at 30, 50, 100, and 200 rpm indicate that much of the mechanical strength of MDF is due to the crosslinked interphase zones that blanket the cement grains. Stresses in the paste due to mixing can destroy the interphase layer, leading to a weaker hardened composite. Microchemical analysis revealed that the mechano-chemistry of the system did not vary with changes in the mixing conditions studied.


2015 ◽  
Vol 3 (9) ◽  
pp. 5014-5022 ◽  
Author(s):  
Surendar R. Venna ◽  
Michael Lartey ◽  
Tao Li ◽  
Alex Spore ◽  
Santosh Kumar ◽  
...  

MOF particles are surface-functionalized to achieve an improved polymer–particle interaction in mixed matrix membranes. Compared to the neat polymer, the membranes have 3 times higher CO2 permeability with ~25% improvement in CO2/N2 selectivity.


2015 ◽  
Vol 22 (8) ◽  
Author(s):  
Jung-Shiun Jiang ◽  
Jau-En Liang ◽  
Han-Liou Yi ◽  
Shu-Hua Chen ◽  
Chi-Chung Hua

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