This article describes an effective strategy for retarding the simultaneous polymer formation during the ethylene oligomerization with bis(imino)pyridine iron catalysts, by addition of siloxanes as modifiers into such systems. The concurrent effects of a suitable siloxane [e.g., tetraethyl orthosilicate (TEOS), cyclohexylmethyldimethoxysilane (CHMMS), or dicyclopentyldimethoxysilane (DCPMS)] are to increase the activity for the soluble oligomers and dramatically decrease the activity for the insoluble polymers, thus synergistically making a pronounced reduction of the polymer share in the total products. Based on the experimental facts when commercial methylaluminoxane (MAO), trimethylaluminum (TMA)‐depleted MAO, and trialkyl aluminums (e.g., TMA) are applied as co‐catalyst, respectively, the functional mechanism of siloxanes is preliminarily discussed. It is proposed that TMA containing in the commercial MAO makes little contribution to the final product but lowers the activity. And, there may be a close relationship between the anionic MAO cages and the insoluble polymer production. The influence of siloxanes exert on the catalyst systems could be a comprehensive result of the interactions between siloxanes and the catalytic components, through the modulation on both the electronic and steric effects of the active centers. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014, 52, 2748–2759

In this work, silicone softener (PTSO-PEG) was synthesized, with piperazine terminated polydimethylsiloxane (PTSO) and epoxy terminated polyethylene glycol (EPEG) as raw materials. Chemical structure of PTSO-PEG was characterized by (1)H NMR, FTIR, GPC, and TGA. Its application on cotton fabrics was studied. Morphologies of silicone modified surfaces on cotton fabrics and silicon wafers were investigated by SEM and AFM, respectively. The morphology images indicated that PTSO-PEG treated surface was macroscopically smooth and microscopically rough. Performance properties of silicone treated cotton fabrics, including hydrophilicity, whiteness, and softness, were tested. The results showed that PTSO-PEG treated cotton fabrics expressed better whiteness and hydrophilicity than traditional amino silicone treated sample. The piperazine and hydrophilic polyether groups on PTSO-PEG molecules disturbed the continuous and orderly arrangement of Si-CH3 groups, giving the cotton a hydrophilic and rough surface. This work provided a cost-effective and environmental method to synthesize and apply high performance silicone softener.

A novel polysiloxane bearing dodecyl and epoxy side groups (DESO) was synthesized as an intermediate through hydrosilylation of polymethylhydrosiloxane with allyl glycidyl ether and 1-dodecene. Then, dodecyl/piperazine functional polysiloxane (DPSO) was prepared through the reaction of N-aminoethylpiperazine with DESO. The chemical structure of DPSO was characterized with FTIR and 1 H-NMR spectroscopy and its application performance on cotton fabrics was studied. DPSO with dodecyl side groups gifted the treated fabrics with good wettability and whiteness compared with piperazine functional polysiloxane, while with a slightly reduced softness as well as thickening handle. Film morphology, orientation, and performance on cotton substrates of DPSO were investigated by scanning electron microscope, atomic force microscopy, X-ray photoelectron microscope, and so on. Affected by the dodecyl side groups, DPSO formed relatively hydrophilic, macroscopically smooth but actually uneven films with many dodecyl side chain pillars on the treated substrate surfaces.