Nucleation and crystallization kinetics of polyamide 12 investigated by fast scanning calorimetry

Abstract

Nucleation and crystallization of polyamide 12 (PA 12) have been systematically investigated by fast scanning calorimetry at non‐isothermal and isothermal conditions. The critical cooling rates of crystallization and crystal nucleation were determined as 300 and 10,000 K/s, respectively. Moreover, the half‐times of nucleation (t1/2,nucl) and overall crystallization (t1/2,cry) show monomodal and bimodal dependencies on the crystallization temperature. t1/2,nucl has an approximate minimum value of about 0.0005 s at 333 K, which is about 10–20 K above the glass transition temperature, and t1/2,cry has two minima of about 0.05 and 0.8 s at about 333 and 383 K, respectively. Comparing the crystallization behavior of PA 12 with other polyamides, the activation energy for crystallization increases and the energy barrier of short‐range diffusion decreases with the increase of the amide‐group density in the chains.

Physical Aging and Glass Transition Dynamics of Semicrystalline Poly(lactic acid) for 3D-Printing Applications Investigated by Fast Scanning Calorimetry

“…As such, after crystallization for 1000 s, the enthalpy-based crystallinity is around 40%. The crystallization-time dependence of the crystal fraction is fitted using an Avrami-based equation considering secondary crystallization with the second term, , χ c = A 1 ( 1 − exp ( − ln ⁡ 2 t t 0.5 ) n ) + A 2 ( ln false( t − t 0.5 , c r y false) ) ( | t − t 0.5 | 2 false( t − t 0.5 false) + 1 ) …”

“…As such, after crystallization for 1000 s, the enthalpy-based crystallinity is around 40%. The crystallization-time dependence of the crystal fraction is fitted using an Avrami-based equation considering secondary crystallization with the second term, , …”

Microbial Biomineralization of Alkaline Earth Metal Carbonates on 3D-Printed Surfaces

“…Following a similar rationale, 33 it is hypothesized that the polymorph, the different coverage, and the pXRD patterns obtained in our experiments are a result of the different surface characteristics of the polymer substrate, such as chemical composition, surface topography, functional group density, and hydrophilic/hydrophobic properties, 30,41,42 some of which are dictated by the polymer processing condition (laser sintering, FDM). 42 Furthermore, it is hypothesized that PLA's relatively hydrophobic nature and unique ester functional groups could influence crystal nucleation and growth, leading to a reduced rate of crystal growth, 30 explaining the more homogeneous coating observed in our experiments. The surface chemistry of PA, which includes polar acrylate groups, may facilitate different interactions at the polymer−water interface, impacting the crystallization behavior as shown in studies on the crystallization of amorphous drugs influenced by polymers 43 accounting for the different biomineralization coverage observed.…”

Effect of copolymerization on the thermal characteristics and behavior of crystallization of biobased semi‐aromatic PA10T/10I

“…This is primarily due to the rigid benzene ring structure, which makes up a sizable portion and decreases the material's toughness and impact performance. The introduction of IPA can properly adjust the mechanical properties of polymers so that controlled mechanical properties make PA10T/10I copolyamides have wider applications to meet multifarious requirements 39 …”

“…The introduction of IPA can properly adjust the mechanical properties of polymers so that controlled mechanical properties make PA10T/10I copolyamides have wider applications to meet multifarious requirements. 39…”