Molecular weight switchable polyurethanes enable melt processing

Advances in Waterborne Polyurethane and Polyurethane-Urea Dispersions and Their Eco-friendly Derivatives: A Review

“…Traditionally, the prepolymer process, designed as an alternative to the patented acetone process, is carried out by synthesizing an NCO-terminated prepolymer of moderate molecular weight (around 8000 g mol −1 ) [ 39 ] comprising the reaction of an isocyanate, a polyol, and an internal emulsifier (usually DMPA). Facing to the importance of achieving high molecular weight polymers due to the need for high performance properties in service [ 47 ], the increase of the molecular weight is later conducted through a chain extension step. Considering the insolubility of the internal emulsifier (in the prepolymer and acetone), a highly polar co-solvent (e.g., NMP) whose high boiling point hinders its removal from the final product, is needed.…”

A one-pot synthesis and X-Ray structural characterization of new highly substituted-allyl carbamates

“…The synthesis of the new -chloro-β,unsaturated alcohols (11, 12 and 14-18) was performed via carbonyl reduction of the -chloro--unsaturated aldehydes. The chlorovinylaldehydes and cinnamaldehyde (1-10) reacted with sodium borohydride as reducing agent in dry THF and gave the products (11)(12)(13)(14)(15)(16)(17)(18)(19)(20) in good yields (Table1).…”

“…Table1: Optimized synthesis of -chloro-β,-unsaturated alcoohols (11)(12)(13)(14)(15)(16)(17)(18)(19)(20).…”

“…Indeed, they belong to structural or functional part of many approved drugs [1][2][3][4][5] and prodrugs [6], which are used for the treatment of various diseases such as Alzheimer's disease [7], cancer [8], hepatitis C [1,9], HIV infection [10], anxiety [11] and epilepsy [11]. They are found to be important raw materials in the synthesis of polyurethanes [12][13][14], paints [15], wood preservatives [15], pesticides, herbicides, insecticides and fungicides [16]. They are also used as intermediates in numerous organic synthesis [17,18] as protecting amino groups in peptide synthesis [19,20], polymers synthesis [21] and as linkers in combinatorial chemistry [22] as well as in the cyclic [23] and heterocyclic compounds synthesis [24][25][26][27].…”

Interpenetrated triple network polymers: synergies of three different dynamic bonds

“…Many studies have shown that SN materials have enhanced mechanical properties by the introduction of dynamic covalent and dynamic non-covalent bonds individually or as a combination of SNs and DNs. [24][25][26][27][28][29] A combination of different crosslinks in one material offers complementary properties such as improved strength, fast shape recovery and toughness. 27,[30][31][32] However, it is still a challenge to simultaneously obtain high mechanical properties and fast (within 1 day), complete self-healing recovery under ambient conditions.…”