Shear-Induced and Nanofiber-Nucleated Crystallization of Novel Aliphatic–Aromatic Copolyesters Delineated for In Situ Generation of Biodegradable Nanocomposites

Abstract

The shear-induced and cellulose-nanofiber nucleated crystallization of two novel aliphatic–aromatic copolyesters is outlined due to its significance for the in situ generation of biodegradable nanocomposites, which require the crystallization of nanofibrous sheared inclusions at higher temperatures. The shear-induced non-isothermal crystallization of two copolyesters, namely, poly(butylene adipate-co-succinate-co-glutarate-co-terephthalate) (PBASGT) and poly(butylene adipate-co-terephthalate) (PBAT), was studied following a light depolarization technique. To have a deep insight into the process, the effects of the shear rate, shear time, shearing temperature and cooling rate on the initiation, kinetics, growth and termination of crystals were investigated. Films of 60 μm were subjected to various shear rates (100–800 s−1) for different time intervals during cooling. The effects of the shearing time and increasing the shear rate were found to be an elevated crystallization temperature, increased nucleation density, reduced growth size of lamella stacks and decreased crystallization time. Due to the boosted nucleation sites, the nuclei impinged with each other quickly and growth was hindered. The effect of the cooling rate was more significant at lower shear rates. Shearing the samples at lower temperatures, but still above the nominal melting point, further shifted the non-isothermal crystallization to higher temperatures. As a result of cellulose nanofibers’ presence, the crystallization of PBAT, analyzed by DSC, was shifted to higher temperatures.

Nanocellulose: Effect on Thermal, Structural, Molecular Mobility and Rheological Characteristics of Poly(Butylenes Adipate-Co-Butylene Terephthalate) Nanocomposites

“…The shear-induced and cellulose-nanofiber nucleated crystallisation were investigated. The author reported that the addition of CNFs did not influence the PBAT crystallinity degree but contributed to the strong increase in the crystallisation temperature [19]. Active packaging films based on nanocomposites of PBAT and cellulose nanofibers (CNS, 5 wt.%) encapsulated with eugenol and linalool were studied.…”

“…An increase in storage modulus, dynamic viscosity and crystallinity was achieved [18]. Hosseinnezhad studied the action of different shear rates on the crystallisation of biodegradable nanocomposites of poly(butylene adipate-co-succinate-co-glutarate-co-terephthalate) poly(butylene adipate-co-terephthalate) (PBAT) filled with cellulose nanofiber [19]. The authors reported induced nucleation upon shearing coexisting with quicker crystallisation, higher density nucleation sites, and thinner lamella stacks.…”

Concurrent effect of shear flow and CNT presence on crystallization behavior and electrical properties of polypropylene based nanocomposites: A comprehensive structure-property investigation

“…[5][6][7] The presence of nanoparticles in the polymer matrix not only influences the crystallization behavior, but also modulates the polymer response to the applied shear, especially when the nucleating nanoparticles are incorporated into the polymer matrix. 8,9 The carbon nanoparticles, including carbon black, carbon fiber, graphite, and carbon nanotube (CNT), in addition to controlling the crystallization behavior, impart electrical conductivity to the polymer. [10][11][12] In this case, shearing affects the electrical conductivity in addition to crystallization.…”

Biodegradable packing food films based on PBAT containing ZnO and MoO3

“…Shah et al 12 have reported several microorganisms and their respective enzymes which could degrade aliphatic, aromatic, as well as aliphatic‐aromatic co‐polyesters like poly(butylene succinate) (PBS), poly(butylene succinate)‐co‐(butylene adipate) (PBSA), poly(ε‐caprolactone) (PCL), poly(ethylene succinate) (PES), poly(L‐lactic acid) (PLA), poly(3‐hydroxybutyrate) (PHB) and poly(3‐hydoxybutyrate‐co‐3‐hydroxyvalterate) (PHB/PHBV), poly(ethylene terephthalate) (PET), poly(butylene terephthalate) (PBT), poly(butylene adipate‐co‐terephthalate (PBAT), poly(butylene succinate‐co‐terephthalate) (PBST), and poly(butylene succinate/terephthalate/isophthalate)‐co‐(lactate) (PBSTIL). To obtain biodegradable polymers with good mechanical properties, several aliphatic‐aromatic copolyesters such as PBAT have been prepared, analyzed and tested 13–17 …”

“…To obtain biodegradable polymers with good mechanical properties, several aliphatic-aromatic copolyesters such as PBAT have been prepared, analyzed and tested. [13][14][15][16][17] The research, preparation and evaluation of organicinorganic hybrid composites is valuable, since it can promote modifications in the original polymeric matrices, such as adding antimicrobial activity, changing thermal degradation temperature and dimensional stability, optical and water vapor barrier properties, wettability, physical and chemical resistance, and do not promote microplastic formation, when they are disposal in the proper place. The appropriate selection of composite elements, as well as their proportions and the obtaining method must be carried out for these changes to configure desired improvements.…”