Synthesis, mesomorphism, orientation and photo‐initiated chain crosslinking of the liquid‐crystalline diacrylate 1,4‐phenylene bis{4‐[6‐(acryloyloxy)hexyloxy]benzoate} (1) are studied. Monomer 1 exhibits a broad nematic phase between 108 and 155°C and a monotropic smectic phase below 88°C. The monomer is uniaxially oriented in its nematic phase at a substrate which has been coated with polyimide and unidirectionally rubbed with tissue. At the transition temperature to the smectic phase the order parameter is measured to be 0,7. During polymerization, the ordering of the mesogens is frozen‐in, yielding a uniaxially crosslinked network. The clear films of oriented poly(1) exhibit a birefringence Δn between 0,12 and 0,15, depending on the polymerization temperature. In the highest oriented state of 1 a small reduction of the degree of order is observed during the crosslinking reaction, whereas at higher temperatures and lower ordering of 1, the uniaxially orientation increases upon reaction. A special feature of the oriented networks is that the ordering is maintained while heating at high temperatures. The polymerization of the acrylate groups in the mesomorphic phases proceeds fast and to high conversion. Below 90°C the polymerization behaviour is similar to that of conventional isotropic diacrylates. Above 90°C the polymerization reaction of the liquid‐crystalline diacrylate proceeds faster than that of an isotropic diacrylate.

Grafting of poly(methyl methacrylate) (PMMA) on microparticulate silica was achieved by initiating the polymerization of MMA by 4,4'-azobis(4-cyanopentanoic acid) that was covalently bound to the silica surface. The initiator seems to be destabilized upon binding it to the silica surface. The kinetics of the graft polymerization are described and are largely affected by the Trommsdorff effect, which makes it possible to graft a high amount of PMMA on silica.

The basic structure of the stereocomplex of isotactic and syndiotactic PMMA was investigated by means of X-ray fiber diffraction. It is shown that the results including a meridional reflection on the ninth layer line can be explained in terms of a 9/1 double-stranded helix, having an asymmetric unit consisting of 1 isotactic unit and 2 syndiotactic units. An apparent 2-fold axis of symmetry is ascribed to the existence of a specific kind of disorder, caused by the fact that there are two ways of intertwining the two chains, related to each other by a rotational angle of about ir. The proposed structure appears to be highly tolerant with respect to structural errors such as chain ends, loops, or inferior stereoregular sequences, explaining the fact that even for samples of low tacticity complex is formed. From the proposed structure, it is suggested that the driving force for complexation is a good sterical fit between the two chains, stabilizing each other's energetically most favorable (close to all-trans) conformation.

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Mesomorphism and the molecular orientation of 1,4‐phenylene bis{4‐(6‐(acryloyloxy)hexyloxy)benzoate} (1) and its derivative with a methyl‐substituent in the central phenylene group (2) are studied. The methyl group affects the transition temperatures and the thermodynamic parameters, but not the order parameter of the monomers. The photoinitiated polymerization of the diacrylate monomers in their uniaxially oriented state leads to highly oriented and densely crosslinked polymer networks. The order parameter of these networks depends on the polymerization temperature, but becomes nearly temperature‐independent after polymerization. The presence of the methyl group leads to a significant lower degree of order in the polymeric state. In addition, data are presented on the monomeric viscosity of 2 and on the tensile moduli, glass transitions and refractive indices of the oriented polymer networks. In order to extend the mesomorphous temperature range, mixtures of 1 and 2 are also investigated.