Polymorphic Behavior and Enzymatic Degradation of Poly(butylene adipate) in the Presence of Hexagonal Boron Nitride Nanosheets

Abstract

Hexagonal boron nitride nanosheets (BNNSs) were prepared by a facile chemical exfoliation method. Then cosolution film casting method was used to obtain poly(butylene adipate) (PBA)/BNNSs nanocomposites. The incorporated BNNSs changed the formation condition of the polymorphic crystals of PBA. The results of differential scanning calorimetry (DSC) and wide-angle X-ray diffraction (WAXD) showed that BNNSs significantly facilitated the formation of α-form crystals for isothermal and nonisothermal crystallization. Compared to pure PBA at 28°C, the α-form crystals would not disappear until the temperature decreased to 13°C with the addition of 0.5 wt % BNNSs. In addition, the excellent heterogeneous nucleation ability of BNNSs was identified by the nonisothermal and isothermal crystallization process. The enzymatic degradation experiments exhibited that PBA/BNNSs nanocomposites possessed a considerably lower degradation rate than neat PBA. This work demonstrates that BNNSs is an efficient material to regulate the formation of polymorphic crystals and the degradation behavior of PBA.

Differential scanning calorimetry study of cross‐nucleation between polymorphs in isotactic poly(1‐butene)

“…In polymers, the use of polymorph‐selective heterogeneous nucleating agents is effective and an industrially appealing solution to control structure formation. For example, γ‐quinacridone red pigment is a very good β‐nucleating agent for isotactic polypropylene, KBr can help to obtain the γ‐modification of poly(vinylidene fluoride), while hexagonal boron nitride nanosheets significantly facilitate the formation of α‐form crystal of poly(butylene adipate) …”

“…For example, -quinacridone red pigment is a very good -nucleating agent for isotactic polypropylene, 8 KBr can help to obtain the -modification of poly(vinylidene fluoride), 9 while hexagonal boron nitride nanosheets significantly facilitate the formation of -form crystal of poly(butylene adipate). 10 In view of a more comprehensive understanding of polymorphic nucleation, cross-nucleation, 11 i.e., the nucleation of one polymorph on another crystalline substrate of the same substance but with different structure, is of importance.…”

Polymorphism and properties of biodegradable poly(1,4‐butylene adipate) tailored using an aliphatic diamide derivative

“…Nucleating agents (NAs) have been widely utilized to alter physical properties and improve various performances (mechanical properties, biodegradation, gas barrier, transparency, electrical conductivity, thermal stability, and so on) of polymeric material, due to the efficiency, low cost, convenience and ease of fabrication of the composite material . Some NAs have been used to manipulate the crystallization behavior, polymorphic crystalline structure and biodegradation of PBA . Owing to weak interface bonding strength between PBA and NA (in particular, inorganic NAs) and insolubility of the NA in the melting PBA matrix, agglomeration (that is, inhomogeneous dispersion) of the NA occurs, resulting in a difficulty in controlling the crystal shape/size and enhancing the nucleation ability.…”

Fractionated crystallization, polymorphism and crystal transformation of poly(butylene adipate) confined in electrospun immiscible blend fibers with polystyrene

“…9 The b crystal can transform to the a crystal by annealing at a relatively high temperature, which has been demonstrated to be a solid-solid transformation process. Therefore, besides temperature, the nucleating agent, [11][12][13][14] blending, 15-20 copolymerization, 10,21,22 substrate, [23][24][25][26] and tension, 9 etc. 10 Polymorphism regulation of PBA is a hot research topic, because both a and b PBA crystals can be easily obtained and stay rather stable under mild conditions compared with other polyesters.…”