Preparation of Temperature-Sensitive Polyurethanes Based on Modified Castor Oil

Abstract

A series of temperature-sensitive polyurethanes (TSPUs) with polytetrahydrofuran glycol (PTMG), poly(ethylene glycol) (PEG) and maleic anhydride modified castor oil (MCO) as soft segments were prepared in this paper. The morphology of the temperature-sensitive polyurethane films was characterised by SEM, DSC and WAXD. SEM studies were also carried out to investigate the surface structure of coated and uncoated fabrics. The water vapour permeability of the coated and uncoated fabrics were measured as well. The results showed that a nonporous TSPU layer was formed on the coated fabric surface. The tailor -made TSPUs had one to three soft segment crystal melting point temperatures, with the the lower peak temperature Tpm1 belonging to the soft segment PTMG and the higher peak temperature Tpm2 to the hydropilic soft segment PEG2000. The water vapour permeability of TSPUs coated fabrics increased with an increase in PEG2000 concentration and PEG molecular weight, but decreased with an increase in the hard segment content, and triggered around the soft segment crystal melting point temperature of TSPUs.

Smart polyester fabric with comfort regulation by temperature and moisture responsive shape memory nanocomposite treatment

“…At 20 � C below T g of SMPU, the air permeability of polyester fabrics decreased proportional to CNW concentration as stated before but as the temperature was raised to 40 � C and 65 � C (above T g of SMPU), air permeability of the treated fabrics, especially PES-SMPU and PES-SMPU-CNW-20 fabrics (from 504 l/m 2 /s to 617 l/m 2 /s for the maximum CNW concentration) increased significantly (Figure 6(b)). Increase in air permeability with temperature (above T g of SMPU), can be explained first by an increase in temperature sensitive free volume [35], micro-Brownian motion [6,28,29] of the soft segments of SMPU matrix that open the permitting passages in inter-molecular gap [28]. Introduction of CNW to the SMPU matrix creates a second mechanism that additional permanent micro-voids occur within the structure and they increase in size and number [59].…”

“…Water vapour transmission feature of fabrics is the one of crucial parameters affecting comfort properties of clothing systems in both high and low temperatures and during undertaking normal and high degree of workload [28]. Therefore, dynamic WVP or breathability change according to environmental temperature and relative humidity creates active thermoregulation function which is crucial for some functional clothing such as sports and protective.…”

“…They are used for thermal comfort enhancements in different forms with their adaptability to dynamic environmental and body physiological changes. Among various thermoresponsive SMPs, SMPU is the most suitable material for textile industry in the form of film [5][6][7][8], fibre to produce fabrics [9][10][11][12][13][14][15][16], fabric coating/finishing applications [17][18][19][20][21][22][23][24][25][26][27][28][29]. SMPU has a two-phase heterogeneous structure consisting of a rigid fixed phase and a soft reversible phase for the shape memory effect [29].…”

“…SMPs containing automatic environmental acclimatizing properties, have wide application potential in the areas of sportswear, work wear and protective clothing [41]. Comfort performance and also active thermoregulation of polyester can be maintained by combining the polyester fibre with SMPU that has the ability of responding to environmental changes, hence, adapting fabric insulation through smart breathability [19,28]. There are applications of SMPU also on fabrics made of different materials such as cotton [24][25][26]29] and wool [32] for smart breathability.…”

Enhancing Wool Fabric Easy Care Properties by Shape Memory Polyurethane Finishing

“…11 The most commonly-used SMPs for smart textile applications are thermally responsive, and among them, SMPU is the most suitable material for the textile industry in various forms of film, 12–15 fibers to produce fabrics, 16–26 and coating/finishing applications. 27–36 SMPU has a characteristic phase-separated structure between hard and soft segments, allowing them to obtain the shape memory effect. 36 The shape memory behavior of thermal-induced SMPU is generally triggered by heating the specimen above the melting ( T m ) or glass transition temperature ( T g ) of the polymer.…”