Jaroslav Stehlíček

Nylon 6 with a short rigid central block

Block copolymers of the general structure nylon 6-short aramid block-nylon 6 were prepared by anionic polymerization of 6-hexanelactam using as precursors of the central rigid block bifunctional initiators having three aromatic rings connected with amide groups in the para-meta-para or para-para-para positions. The effects of the type and concentration of the central block on the crystallization of nylon 6 component were studied by WAXS, SAXS, DSC and optical microscopy.

Low‐filled toughened composites of poly(hexano‐6‐lactam)‐block‐polybutadiene‐block‐poly(hexano‐6‐lactam)/wollastonite by polymerization casting

Composites consisting of 10–15 wt % wollastonite as an acicular filler and poly(hexano-6-lactam)-block-polybutadiene-block-poly(hexano-6-lactam) matrix (5–15 wt % polybutadiene blocks) were prepared by anionic polymerization of hexano-6-lactam. Hydroxyterminated polybutadiene in situ functionalized with toluene-2,4-diyl diisocyanate (TDI) was used as an initiator and sodium salt of hexano-6-lactam as a catalyst. To achieve a good dispergation and high adhesion to the matrix, the filler was modified with (3-aminopropyl)triethoxysilane and then functionalized either separately with N,N′-benzene-1,3-dicarbonylbis(hexano-6-lactam) or N-benzoyl-hexano-6-lactam or in situ functionalized with TDI. The increase in Youngs modulus and decrease in elongation were achieved along with a moderate decrease in impact resistance.

Block copolymers of 6-hexanelactam and 12-dodecanelactam

Abstract Poly(6-hexanelactam)- block -poly(12-dodecanelactam) (polyamide-6- block -polyamide-12) diblock copolymers containing a small portion of the corresponding homopolymers were prepared by the anionic polymerization of 6-hexanelactam using poly(12-dodecanelactam)s with diacylamine branching sites as precursors of polymeric initiators (PPI). The PPI were prepared by the acidolytic copolymerization of 12-dodecanelactam with N -benzoyl-12-dodecanelactam. The effect of PPI molecular structure on the composition and properties of the block copolymers was followed.

Properties of aliphatic block copolyamides and homopolyamide blends prepared by combined polymerization

Poly(6-hexanelactam)-block-poly(12-dodecanelactam) copolymers containing a minor part of poly-(6-hexanelactam) (PA6) and poly(12-dodecanelactam) (PA12) were compared with PA6-PA12 blends as regards their crystallization behaviour, thermal properties, sorption of water vapour, morphology and mechanical properties. All blends were prepared by the combined polymerization procedures described earlier. The differences found are ascribed to the different composition of amorphous phases, specifically to the compatibilization effect of the diblock copolymer.

Synthesis and properties of copolymers consisting of aramide and poly(6-hexanelactam) blocks

Abstract Low molecular weight aromatic polyamides of the meta-type which bear N-acyl-6-hexanelactam end-groups were prepared, characterized by NMR and utilized as initiators of the anionic polymerization of 6-hexanelactam. The resulting block copolymers poly(6-hexanelactam)-block-poly(-isophthalic acid-alt-2-methyl-1,3-phenylenediamine)-block-poly-(6-hexanelactam) were characterized by NMR, DSC, TGA, X-ray diffraction and microscopy of solution-cast films and compared with an aramide-polyamide 6 blend also prepared by polymerization.