Ulrich Schulze

Synthesis, electron irradiation modification and characterization of polyethylene/poly(butyl methacrylate-co-methyl methacrylate) interpenetrating polymer network

WWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWW WWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWW WWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWW WWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWW The present work reports the preparation of a porous structure by electron beam irradiation of interpenetrat- ing polymer network (IPN) based on polyethylene and poly(methyl methacrylate-co-butyl methacrylates). Thin IPN films were synthesized by in situ polymerization. Low-density polyethylene (PE) was used as the first IPN component, and the second IPN component was formed by copolymerization of methyl methacrylate and butyl methacrylate. After the synthesis the methacrylic phase is finely dispersed in a PE matrix. Porous films of these materials were obtained by decomposition of the polymethacrylate phase by means of electron radiation followed by extraction with xylene. The thermal stability in N2 atmosphere of the irradiated and extracted IPN was improved compared with the unirradiated samples. Three temperature regions of weight loss were observed, two of them caused by the copolymer and one by the PE. The lowering of the melting temperature of PE observed by differential scanning calorimetry analysis indicated an increase in crosslinking caused by irradia- tion. Morphology changes were studied by scanning electron microscopy which revealed a porous surface structure of the irradiated and extracted samples. Flux measurements showed that some irradiated samples were permeable to ethanol, demonstrating an interconnected porous structure which may be relevant for membranes.

Synthesis of Various Functional Propylene Copolymers Using rac‐Et[1‐Ind]2ZrCl2/MAO as the Catalyst System

Propylene copolymers with different polar groups were synthesised using rac-Et[1-Ind] 2 ZrCl 2 /MAO as the catalyst system. 10-Undecen-1-ol, 10-undecenoyl chloride, 10-undecenoic acid, 2-(9-decen-1-yl)-1,3-oxazolien, 2-(9-decen-1-yl)-4,4-dimethyl-1,3-oxazoline, and 2-[4-(10-undecene-1-oxy)phenyl]-1,3-oxazoline were used as comonomers. The addition of water to the 10-undecenoyl chloride copolymer solution led to an acid-functionalised copolymer. In the case of 2-(9-decen-1-yl)-1,3-oxazoline and its homopolymers, polymerization temperature was varied. Up to 0.61 mol-% comonomer were incorporated into the poly(propylene)s. The catalyst activities for 10-undecen-1-ol, 10-undecenoyl chloride and 10-undecenoic acid were much higher than for the oxazoline comonomers.

Synthesis of oxazoline functionalized polypropene using metallocene catalysts

Using two different zirconocene/MAO catalyst systems, propene was copolymerized with the comonomers 2-(9-decene-1-yl)-1,3-oxazoline and 2-(4 (10-undecene-1-oxo)phenyl)-1,3-oxazoline, respectively. The catalysts used were rac-Et[Ind] 2 ZrCl 2 and rac-Mc 2 Si[2-Me-4, 5-BenzInd] 2 ZrCl 2 . Up to 0.53 mol-% oxazoline could be incorporated into polypropene. Oxazoline ontent, molecular weight, degree of isotacticity and melting behavior were dependent on the catalyst system, comonomer structure and comonomer concentration in the feed.

Spectroscopic Examinations of Hydrogen Bonding in Hydroxy‐Functionalized ADMET Chemistry

Wide-angle X-ray scattering (WAXS) and temperature-dependent Fourier transform infrared spectroscopy (FTIR) spectroscopy are used to study hydrogen bonding interactions of a hydroxyl-functionalized polyethylene (PE) prepared by acyclic diene metathesis (ADMET) chemistry. The hydroxyl polymer exhibits an orthorhombic unit cell structure with characteristic reflection planes at (110) and (200), comparable to pure crystalline PE. These data unequivocally demonstrate that the OH branch is excluded from the PE lamellae. Furthermore, the polymer melts 100 °C higher than all previous analogous polymers possessing precision placed long aliphatic branches that also are excluded from PE lamellae. Temperature-dependent FTIR spectroscopy from ambient to 150 °C, followed by cooling to 125 °C supports exclusion of the hydroxyl group from the crystalline lattice. It is concluded that these hydroxyl groups form stable physical networks in the amorphous region via hydrogen bonding and are important for the overall morphology of such polymers.