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Block co-polymers can have several properties that are not present in comparable statistical co-polymers, and interest in studying their properties has increased considerably during recent decade [1]. Block co-polymers can have, for example, the ability to form self-organized structures [2]. Especially co-polymers consisting of PDM (poly[2-(dimethylamino)ethyl methacrylate]), PEO (poly(ethylene oxide)), and/or PPO (poly(propylene oxide) blocks have found applications in the field of hydrophobizing paper [3] or other hydrophilic surfaces [4], strengthening agents for wood fibre networks [5,6] and even some biomedical applications [2]. In addition, some special solution properties have been found for copolymers containing cationizable PDM block. E.g. at high pH PEO-b-PDM will aggregate at the temperature where the PDM sequence is totally deprotonated and sufficiently hydrophobic [7]. PDM can also easily be modified into a permanently cationic form by methylation of the tertiary amine group to form a quaternary amine [8,9]. Abstract. To modify the rheological properties of certain commercial polymers, a set of block copolymers were synthesized through oxyanionic polymerization of 2-(dimethylamino)ethyl methacrylate to the chain ends of commercial prepolymers, namely poly(ethylene oxide) (PEO), poly(ethylene oxide)-block-poly(propylene oxide)-block-poly(ethylene oxide) (PEO-PPO-PEO), and poly(propylene oxide) (PPO). The formed block copolymers were analysed with size exclusion chromatography and nuclear magnetic resonance spectroscopy in order to confirm block formation. Thermal characterization of the resulting polymers was done with differential scanning calorimetry. Thermal transition points were also confirmed with rotational rheometry, which was primarily used to measure melt strength properties of the resulting block co-polymers. It was observed that the synthesised poly[2-(dimethylamino)ethyl methacrylate]-block (PDM) affected slightly the thermal transition points of crystalline PEO-block but the influence was stronger on amorphous PPO-blocks. Frequency sweeps measured above the melting temperatures for the materials confirmed that the pre-polymers (PEO and PEO-PPO-PEO) behave as Newtonian fluids whereas polymers with a PDM block structure exhibit clear shear thinning behaviour. In addition, the PDM block increased the melt viscosity when compared with that one of the pre-polymer. As a final result, it became obvious that pre-polymers modified with PDM were in entangled form, in the melted state as well in the solidified form.

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Three-dimensional (3D) printing of biomaterials has the potential to become an ecologically advantageous alternative compared with conventional manufacturing based on oil-derived polymer materials. In this study, a novel 3D printing technology is applied that combines ultraviolet (UV) curing with paste extrusion. This hybrid manufacturing technique enables the fabrication of complex geometries from high filler-ratio pastes. The developed biocomposite aims for suitable mechanical properties in terms of tensile and compressive strength. It is composed of acrylic acid, cellulose acetate, a-cellulose, and fumed silica with a cellulose ratio of more than 25 vol-%. The material is extruded with an in-house-developed 3D printer equipped with a 12 W UV light curing source, which enables concurrent curing and extrusion. Two different UV-curing strategies were tested: postcuring without concurrent curing and postcuring with concurrent curing. The total UV-curing duration was kept constant with all samples. Tensile testing in accordance with ASTM standard D638-14 Type 4, compression testing according to ASTM D695-15, and overhang tests were conducted. As a result, samples without notable shrinkage, suitable tensile strength (up to 17.72 MPa), competitive compression testing parameters (up to 19.73 MPa), and an enhanced overhang angle (increase of more than 25°) were produced, leading to new applications and more freedom in design due to higher possible unsupported overhangs when using UV-curing during the print. Overall, constant UV light radiation during the print leads to improved mechanical properties due to the possibility of bypassing the UV-penetration depth constraint. It should be considered when extruding photopolymer-based composites, especially for large and complex components with a low degree of translucency.

We synthesized a new weakly interacting monomer with a reactive phenylsilane group that is an intermediate for many functional groups. The synthesis was performed in two steps: the hydrosilylation of 1,7‐octadiene with dimethylchlorosilane and a Grignard reaction with phenyl magnesium bromide. The new monomer, 7‐octenyldimethylphenylsilane, was isolated and copolymerized with ethylene via metallocene catalysts (Me2Si(Me‐2‐Ind)2ZrCl2 and Et(Ind)2ZrCl2) and methylaluminoxane (MAO) as a cocatalyst. Electropositive silicon had no negative effect on the copolymerization reaction. The polymerization activity increased, and the molar mass of the product remained at a high level. The comonomer incorporation reached a significant 11.8 wt % (2.6 mol %). © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 1303–1308, 2002