Isocyanate‐ and Solvent‐Free Route to Thermoplastic Poly(amide‐urea) Derived from Renewable Resources

Abstract

This study reports on tailoring biobased aliphatic poly(amide‐urea) (PAU) thermoplastics by means of reactive extrusion requiring neither the use of diisocyanate monomers nor time‐consuming PAU polycondensation in a separate step prior to melt processing. Key intermediate is N,N′‐carbonyl‐biscaprolactam (CBC), which enables rapid and temperature‐programmable polycondensation of biobased diamines and difunctional aminoamides (AA) derived from diamines and dicarboxylic acids. Within a few minutes during melt processing using a twin‐screw extruder, CBC‐mediated advancement of biobased diaminoamides affords high molecular weight PAU. Whereas PAUs derived from short‐chain AAs are stiff and brittle materials with high melting temperatures close to thermal decomposition; the incorporation of AAs derived from sebacic acid and dimer fatty acid renders urea‐functional thermoplastics flexible and processable. Hence, the variation of oligomethylene segment lengths by incorporating short‐ and long‐chain AA building blocks in CBC‐mediated melt‐phase polycondensation governs PAU melting temperature (124–249 °C), Young's modulus (100–1900 MPa), tensile strength (6–51 MPa), and elongation at break (0.3–230%).

New Kind of Thermoplastic Polyurea Elastomers Synthesized from CO2 and with Self-Healing Properties

“…However, the notorious toxicity of di- or polyisocyanates has a severe impact on human health and the surrounding environment. In addition, the PU produced from isocyanates are not melting processable and recyclable, as their melting temperatures are near the thermal decomposition temperature due to the quadruple strong and regular intermolecular hydrogen bonds and the cross-linking structure formed in the reaction of isocyanate with urea group . Thus, the use of an environment-friendly reagent replacing the isocyanate to synthesize nonisocyanate PU is highly appreciated.…”

New Insights into Segmental Packing, Chain Dynamics and Thermomechanical Performance of Aliphatic Polyurea Composites: Comparison between Silica Oxides and Titanium (III) Oxides

“…In response to these hazards, several solvent-free routes to PU exist in the new literature. [25][26][27] Synthesis of poly(dimethylsiloxane) based-semicrystalline PU with tunable crystalline melting points exhibited high strain at break between 495% and 1180%, as reported by Sirrine et al [25] However, the low HS content (4.0 wt%) led to an ultimate tensile strength of only 1.16 MPa. On the other hand, a non-solvent route using diphenyl carbonates [27] achieved higher stress and elongation at break results of 17 MPa and 681%, respectively.…”

A Review on CO2‐Based Polyureas and Polyurea Hybrids

“…[71] Poly(amide-urea) (PAU) thermoplastics were produced via the one-step temperature-programmed rapid polycondensation of N,N'-carbonyl-biscaprolactam (CBC) and difunctional aminoamides (AAs) by melt processing (Scheme 22). [72] CBC could readily be obtained by reacting ɛ-caprolactam with DPC or urea. Eight AA monomers were obtained via the reaction of diamines (DA4, HDA and DAD) with diethylesters of adipic acid, sebacic acid, or a dimerized fatty acid (PRIPOL 1009).…”