Relationships between Architectures and Properties of Highly Branched Polymers: The Cases of Amorphous Poly(trimethylene carbonate) and Crystalline Poly(ε-caprolactone)

Abstract

Highly branched polymers (HBPs) are a special class of functional polymeric materials and possess unique properties due to their unique topological structure. A new series of highly branched linear-comb and star-comb amorphous poly(trimethylene carbonate)s (PTMC) and crystalline poly(ε-caprolactone)s (PCL) with well-defined structure and high molecular weight were first synthesized using hydroxylated polybutadiene (HPB) as macroinitiators by simple "one-step" and "graft from" strategies. It is expected that the impact of long-chain, highly branched architecture on the properties of amorphous and crystalline polymers, respectively, is different. We explored systematically for the first time the effect and comparison of branched architectures on the physical and chemical properties of highly branched PTMCs and PCLs, including the intrinsic viscosity, glass transition, thermal degradation, creep property, rheological property, and crystallization and melting behaviors. It is found that the intrinsic viscosities in solution for both comb-branched PTMCs and PCLs were much lower compared with their linear and star counterparts arise from more compact structure and smaller hydrodynamic volumes. For amorphous PTMC, the creep strain and rate increased remarkably with degree of branching increasing due to the shorter side chains making it difficult for the highly branched molecules to entangle. For crystalline PCL, both WAXD and DSC analysis of PCLs with different topological structures indicated that the comb branched architectures have no significant influence on the crystal structure of PCL, but greatly promote the crystallization behavior, e.g., higher crystallinities. The deep understanding of structure-property relationship expects to guide the synthesis of designed functional polymer materials and the processing of polymer products.

Novel branched poly(ɛ‐caprolactone) as a nonmigrating plasticizer in flexible PVC: Synthesis and characterization

“…In such a case, information on DB can be alternatively achieved from other measurements. For example, Ren et al . and Pitet et al .…”

“…The intrinsic viscosity value of D X in our research was determined in THF with a Ubbelohde viscometer at 30 °C. The K and α for the linear PCL initiated by benzyl alcohol were reported to be 2.77 × 10 −4 dL/g and 0.677, respectively . The intrinsic viscosity values of linear PCL samples with identical molecular weights to D X were calculated based on MHS relationship [eq. ]…”

Conformational and hydrodynamic parameters of hyperbranched pyridylphenylene polymers

“…The analysis of HBPs and modified materials is mainly focused on the determination of physicochemical properties such as intrinsic viscosity, glass transition, thermal degradation, rheological property, crystallization and melting behaviour and their influence on the degree of branching. Notwithstanding the enormous efforts and a large amount of data available, a definite relationship between the architecture and the conformation of hyperbranched macromolecules and their physical properties has not yet been established …”

Synthesis and characterisation of highly branched polyisoprene: exploiting the “Strathclyde route” in anionic polymerisation

“…The increase in the degree of branching, at the same time, can cause an increase in the molecular mobility due to an increase in the free volume of the molecular chains. [52][53][54] As can be seen in Table 2, samples B7, B8 and B10 having the lowest g 0 possess the lowest T g values. Sample B9, on the other hand, has the highest T g values possibly due to the high molecular weight as well as high DVB content.…”