Synthesis of Heteroarm Star-Shaped Block Copolymers with Cyclotriphosphazene Core and Their Compatibilizing Effects on PPO/Nylon 6 Blends

Abstract

The preparation and compatibilizing ability of heteroarm star-shaped block copolymers (6 and 8) composed of polystyrene and nylon 6 units diverged from the phosphazene core were investigated. The heteroarm star-shaped copolymers were prepared by a partial coupling reaction of the acid chloride of hexakis(4-carboxyphenoxy)cyclotriphosphazene [4, (4-ClCOC6H4O)6N3P3] with polystyrene having a terminal amino group (PSt−NH2) or poly(styryllithium), followed by the ring-opening polymerization of ε-caprolactam (ε-CL) with the residual carboxyl group in the phosphazene core. The coupling reaction of telechelic PSt−NH2 and poly(styryllthium) with 4 occurs smoothly to give carboxyphenoxycyclotriphosphazenes carrying 2.2−4.7 polystyrene chains, 5 and 7, respectively. The polymerization of ε-CL with hexakis(4-carboxyphenoxy)cyclotriphosphazene [2, (4-HOOCC6H4O)6N3P3] showed that all carboxyl groups participate in the initiation of polymerization to give hexaarmed star-shaped polymers. This implies that the residual carboxyl groups in 5 and 7 could also initiate the polymerization of ε-CL. The molecular weights of copolymers obtained from the polymerization of ε-CL with 5 and 7 are in agreement with those of calculated values, suggesting the formation of heteroarm star-shaped block copolymers with phosphazene core (6 and 8). When these copolymers were used as a compatibilizer of an immiscible blend, poly(2,6-dimethylphenylene oxide) (PPO) and nylon 6, DSC profiles showed a single transition temperature that shifted to lower temperature from the T g of PPO. The SEM photograph indicates that PPO disperses regularly and finely with 0.3 μm size in the nylon domain. Furthermore, the tensile strength and elongation at break of ternary blends increased with increasing the copolymer content. These results indicate that the effective penetration of each block sequence of the heteroarm star-shaped copolymers into the blend components is operative, that is, these copolymers act as an excellent compatibilizer for PPO/nylon 6 blends.

Synthesis and characterization of star-branched polyamide 6 via anionic ring-opening polymerization with N , N′ , N″ -trimesoyltricaprolactam as a multifunctional activator

“…In contrast to the traditional commercial linear PA6 product, star-branched polyamide 6 (SPA6) has drawn the academic and industrial interest for the increased performance with potential advantages in engineering applications [6][7][8][9]. Various synthetic routes to SPA6 have been established through different polymerization mechanisms.…”

Compatibilization of poly(2,6‐dimethyl‐1,4‐phenylene oxide)/polyamide 6 blends with styrene–maleic anhydride copolymer: Mechanical properties, morphology, crystallization, and melting behavior

“…Poly(2,6‐dimethyl‐1,4‐phenylene oxide) (PPO) has high tensile strength, good dimensional stability, good water resistance, and high glass‐transition temperature, but it also possesses low melt flow ability and poor processability, natural brittleness, and poor solvent resistance 1–3. Polyamide 6 (PA6) has good melt flow ability and excellent solvent resistance with deficiencies like poor water resistance, poor heat resistance, and low dimensional stability 4–6.…”

Synthesis, characterization, and in vitro degradation of star‐shaped P(ε‐caprolactone)‐b‐poly(L‐lactide)‐b‐poly(D,L‐lactide‐co‐glycolide) from hexakis [p‐(hydroxymethyl)phenoxy]cyclotriphosphazene initiator

“…Moreover, cyclotriphosphazenes could be used as multifunctional initiators. 48,49 In our previous study, star-shaped PLA and star-shaped diblock copolymer PCL-b-D,L-PLAGA initiated with cyclotriphosphazenes were synthesized. 50,51 However, there are still some questions should be answered.…”