Quantitative characterization of kaolinite dispersibility in styrene–butadiene rubber composites by fractal dimension

A fractal method was introduced to quantitatively characterize the dispersibility of modified kaolinite (MK) and precipitated silica (PS) in styrene–butadiene rubber (SBR) matrix based on the lower magnification transmission electron microscopic images. The fractal dimension (FD) is greater, and the dispersion is worse. The fractal results showed that the dispersibility of MK in the latex blending sample is better than that in the mill blending samples. With the increase of kaolinite content, the FD increases from 1.713 to 1.800, and the dispersibility of kaolinite gradually decreases. There is a negative correlation between the dispersibility and loading content. With the decrease of MK and increase of PS, the FD significantly decreases from 1.735 to 1.496 and the dipersibility of kaolinite remarkably increases. The hybridization can improve the dispersibility of fillers in polymer matrix. The FD can be used to quantitatively characterize the aggregation and dispersion of kaolinite sheets in rubber matrix.

Influence of the structural characteristic of pyrolysis products on thermal stability of styrene-butadiene rubber composites reinforced by different particle sized kaolinites

A series of rubber composites were prepared by blending styrene-butadiene rubber (SBR) latex and the different particle sized kaolinites. The thermal stabilities of the rubber composites were characterized using thermogravimetry, digital photography, scanning electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy, and Raman spectroscopy. Kaolinite SBR composites showed much greater thermal stability when compared with that of the pure SBR. With the increase of kaolinite particle size, the pyrolysis products became much looser; the char layer and crystalline carbon content gradually decreased in the pyrolysis residues. The pyrolysis residues of the SBR composites filled with the different particle sized kaolinites showed some remarkable changes in structural characteristics. The increase of kaolinite particle size was not beneficial to form the compact and stable crystalline carbon in the pyrolysis process, and resulted in a negative influence in improving the thermal stability of kaolinite/SBR composites.

Influence of kaolinite particle size on cross-link density, microstructure and mechanical properties of latex blending styrene butadiene rubber composites

Cross-link density, microstructure and mechanical properties of styrene butadiene rubber (SBR) composites filled with different particle sized kaolinites are investigated. With the increase of kaolinite particle size, the cross-link density of the filled SBR composites, the dispersibility and orientation degree of kaolinite particles gradually decrease. Some big cracks in filled rubber composites are distributed along the fringe of kaolinite aggregates, and the absorbance of all the absorption bands of kaolinites gradually increase with the increase of kaolinite particle size. All mechanical property indexes of kaolinite filled SBR composites decrease due to the decrease of cross-linking and reduction of interface interaction between filler and rubber matrix.

Regulating unilateral supermarket misconduct as customer/acquirer of goods and services

Supermarkets in Australia may have substantial market power as buyers in wholesale markets for grocery products. They may also have substantial bargaining power in negotiating contracts with their suppliers of grocery products. The Competition and Consumer Act 2010 (Cth) (CCA) regulates misconduct by supermarkets as customer/acquirers in three ways. First, s 46(1) of the CCA prohibits the ‘taking advantage’ of buyer power for the purpose of damaging a competitor, preventing entry or deterring or preventing competitive conduct. Secondly, s 21 of the ACL prohibits unconscionable conduct in business–to–business transactions. Thirdly, Pt IVB of the CCA provides for the promulgation of mandatory and voluntary industry codes of conduct. Since 1 July 2015 the conduct of supermarkets as customer/acquirers has been regulated by the Food and Grocery Industry Code of Conduct. This article examines these three different approaches. It considers them against the background of the misconduct at issue in ACCC v Coles Supermarkets Australia Pty Ltd which the ACCC chose to litigate as an unconscionable conduct case, rather than a misuse of market power case. The article also considers the strengths and weaknesses of each of the three approaches and concludes that while the three approaches address different problems there is scope for overlap and all three should be retained for compete coverage.

How social preferences shape incentives in (experimental) markets for credence goods

Credence goods markets suffer from inefficiencies caused by superior information of sellers about the surplus-maximising quality. While standard theory predicts that equal mark-up prices solve the credence goods problem if customers can verify the quality received, experimental evidence indicates the opposite. We identify a lack of robustness with respect to heterogeneity in social preferences as a possible cause of this and conduct new experiments that allow for parsimonious identification of sellers’ social preference types. Our results confirm the assumed heterogeneity in social preferences and provide strong support for our explanation of the failure of verifiability to increase efficiency.