# Novel Applications of Successive Self-nucleation and Annealing Thermal Fractionation for Polymer Characterization

## TL;DR

This review explores how a thermal method called SSA helps analyze and improve sustainable and recyclable polymers by revealing their structural details.

## Contribution

The paper reframes SSA as both an analytical and structure-directing tool for sustainable polymer design.

## Key findings

- SSA reveals lamellar and molecular heterogeneities in semicrystalline polymers.
- SSA aids in understanding crystallization behavior in biodegradable and recycled materials.
- SSA bridges kinetic and thermodynamic regimes to refine polymer structures.

## Abstract

Successive self-nucleation and annealing (SSA) has evolved
into
a highly sensitive thermal fractionation protocol capable of resolving
subtle lamellar and molecular heterogeneities in semicrystalline polymers.
Its relevance has intensified over the past decade as SSA has been
applied to sustainable, biobased, biodegradable, and mechanically
recycled materials, as well as to systems in which crystallization
behavior is tightly linked to circularity, processability, and final
performance. In this review, we integrate nearly three decades of
SSA developments from a longitudinal perspective, placing particular
emphasis on how the role and interpretative power of SSA have progressively
expanded in material classes that play a key role in sustainability
and recyclability, including aliphatic polyesters and biodegradable
copolymers, isodimorphic and mixed-mode random copolymers, nanocomposites
with complex interfacial crystallization, and recycled polyolefins
and biobased blends. Rather than re-establishing already standard
protocols, we briefly revisit the experimental foundations of SSA
to provide a self-contained framework that supports the interpretation
of these applications, highlighting the influence of key variables
such as starting temperatures based on self-nucleation temperature
(T

s
), holding times at T

s
(t

s
), fractionation windows (ΔT

s
), and scanning rates. We then examine
how SSA can elucidate comonomer inclusion/exclusion ratios, topology-driven
annealing, interfacial nucleation (supernucleation, prefreezing, and
antinucleation), and lamellar reorganization during mechanical recycling.
Finally, we highlight SSA as an intermediate crystallization condition
that bridges kinetic and thermodynamic regimes, enabling refined lamellar
populations and amplifying subtle thermal or polymorphic transitions.
By reframing SSA as both an analytical and structure-directing crystallization
tool, this review provides an integrated roadmap for researchers aiming
to exploit its full potential in the rational design of sustainable,
recyclable, and high-performance semicrystalline polymers.