We report on the synthesis of poly(homo-isobutylene) and poly(homo-R-methylstyrene) and the thermal properties of these new polymers. Based on the ring-opening metathesis polymerization (ROMP) of 3,3-dimethylcyclopropene and 3-methyl-3-phenyl-cyclopropene, the respective ring-opened polymers were generated. Several catalytic systems (first-generation (I), second-generation (II), third-generation Grubbs-type (IV) and the Schrock-type initiator Mo(N-2,6-iPr 2 C 6 H 3 )(CHCMe 2 Ph)(OCMe 3 ) 2 (III) were used. Particularly II, III and IV offered access to living polymerization reactions in the case of 3-methyl-3-phenyl-cyclopropene, however, not with 3,3-dimethylcyclopropene. The obtained ROMP-polymers were hydrogenated using tosylhydrazide, furnishing poly(homo-isobutylene) and poly(homo-R-methylstyrene) in high yields. Thermal-measurements (DSC-measurements) revealed T g -and T m -values located between those of poly(isobutylene), poly(styrene), and high-density poly(ethylene).

We report on the monitoring and evaluation of the crossover reaction in ring-opening metathesis polymerization (ROMP) via MALDI methods. ROMP of various monomers using several catalytic systems (first-generation (I) and third-generation Grubbs-type (III)) was investigated with structurally different norbornene monomers derived from (±)endo,exo-bicyclo[2,2,1]-hept-5-ene-2,3-dicarboxylic acid-bis-O-methyl ester (monomer A), (±)endo,exo-bicyclo[2,2,1]-hept-5-ene-2,3-dicarboxylic acid-bis-O-2,2,6,6-tetramethyl piperidinoxyl-ester (monomer T), (±)exo-N-(4,4,5,5,6,6,7,7,7-nonafluoroheptyl)-10-oxa-4-azatricyclodec-8-ene-3,5-dione (monomer D), and the highly strained monomer 2-methyl-2-phenyl-cyclopropene (monomer E). The crossover reactions as well as the polymerization kinetics of the various monomers were studied in detail, in particular, using matrix-assisted laser desorption ionization mass spectrometry (MALDI). Catalyst III offered access to the synthesis of highly defined block copolymers, generating poly(A-b-T), poly(A-b-D), and poly(A-b-E) diblockcopolymers in high precision, whereas catalyst I offered access to the diblockcopolymers poly(A-b-D) and poly(A-b-E). Poly(A) was used as a probe to analyze the crossover reaction, revealing well-defined crossover kinetics in the case of monomers T, D, and E and a subsequent good polymerization after the crossover reaction in the case of monomer E. The presented system allows a simple evaluation and monitoring of crossover reactions in ROMP-based polymerization reactions.

Structure and dynamics of two microphase-separated norbornene block copolymers containing one comb-like component are investigated by X-ray scattering, relaxation spectroscopy as well as differential scanning calorimetry. It is shown that two self-assembling processes on different length scales coexist for these copolymers leading to hierarchically structured systems. Microphase separation of both block copolymer components appears on a scale of 20-25 nm while norbornene main and long semifluorinated side chains of the comb-like block nanophase separate within their domains on a scale of about 3 nm. This hierarchical structure is accompanied by a complex relaxation behavior which is characterized by two glass transitions. The glass temperature of the block with long bulky side chains is expectedly lower due to internal plasticization. An additional relaxation process showing typical features of a dynamic glass transition is related to an independent dynamics in small nanodomains formed by long aggregated side chains similar to the findings for many other comb-like polymers. Indications for the disappearance of the nanophase separation of main and semifluorinated side chains at high temperatures are discussed.