**3. PU from SO FAD**

412 Polyurethane

**2. SO based diols** 

starting SO.

(65‐80 % oleic acid)

extender, cross‐linker, reaction temperature and other reaction conditions. In this chapter we have focussed on the preparation, structure and properties of PU obtained from diols, triols and polyols derived by amidation of SO termed as "SO alkanolamides". In the proceeding sections, we have also discussed the modifications of the said SO alkanolamides based PU at the forefront of PU chemistry such as SO based metal containing PU, PU

The most excessively used SO based diol in PU production is fatty amide diol or fatty alkan‐ diol‐amide [FAD] (Figure 2). FAD is obtained by the base catalysed amidation of SO with diethanolamine. The structure of FAD is determined by the fatty acid composition of the

**Figure 2.** Figure 2. FAD from (a) Linseed (35.0‐60.0 % Linolenic acid), (b) Soybean (43.0‐56.0 % Linoleic acid) and (c) Karanj (44.5–71.3 % oleic acid), Nahor (55‐66% oleic acid) , Jatropha (37‐63 % oleic), Olive

hybrids, composites for applications mainly in coatings, paints and foams.

FAD can be treated with an isocyanate such as TDI, IPDI, HMDI, MDI, ND, CHDI and LDI forming poly (urethane fatty amide) (Figure 3) [FADU] [31].

**Figure 3.** FADU from (a) Linseed, (b) Soybean (c) Karanj, Nahor, Jatropha, Olive and (d) Castor

For the first time, Linseed oil [LO] derived FAD [LFAD] was treated with TDI by one‐shot technique to prepare PU [LFADU] as introduced by Ahmad et al [32] (Figure 4).

Seed Oil Based Polyurethanes: An Insight 415

**Figure 5.** Chemical structure of PFADU or NFADU

fatty alkyl chains, respectively.

FADU from NO [NFADU] [26].

The thermal degradation of PFADU was observed at 177oC and 357oC, with 5% weight loss occurring at 200oC attributed to the entrapped solvent and moisture, 10wt% loss at 225 oC, attributed to the decomposition of urethane moieties, 50wt% and 80wt% losses at 390 oC and 455 oC, respectively, attributed to the degradation of the aromatic ring and aliphatic pendant

It was observed that in both LFADU and PFADU, beyond 1.5moles loading of TDI, formation of some lumpy aggregates occurred. Upto 1.5 moles of TDI addition, it is speculated that the isocyanate groups of TDI react with hydroxyl groups of FAD forming PU linkages. Beyond this amount, any additional isocyanate added reacts with the urethane groups of LFADU or PFADU forming allophanate groups (secondary reaction). The final PU attains very high viscosity and crosslinking, so much so that the formation of lumpy

Karak and Dutta have reported the production of PU by amidation and urethanation of methyl ester of *M. Ferrea* or Nahor oil [NO], rich mainly in triglycerides of linoleic, oleic, palmitic and stearic acids. They investigated the structure and physico‐chemical aspects of

aggregates occurs and PU is deprived off its free flowing tendency.

**Figure 4.** Chemical structure of LFADU.

The structure of LFADU was established by spectral analyses. FTIR, 1H NMR and 13C NMR spectra showed the presence of the main characteristic absorption bands of parent SO [32]. Along with these bands, additional absorption bands are observed supporting the presence of urethane groups in the backbone of LFADU such as those at 3375cm−1 for hydroxyl groups, 1716.11 cm−1 for urethane carbonyl (str), 1227.56cm−1 for C–N of urethane groups, 1735cm−1 typical for carbonyl (str) of TDI. The characteristic peaks for hydrogen bonded and non‐hydrogen bonded protons of –**H**NCOO– appear at 7.99–7.82ppm and 7.1–6.9ppm, respectively. The aromatic ring protons of TDI occur at 7.5–7.22 ppm. The peaks of – **H**NCOOCH2– are observed at 4.1–3.9ppm and for C**H**3 of TDI appear at 2.25ppm. 13C NMR spectrum also shows the presence of characteristic peaks of LFADU at 17ppm (**C**H3 of TDI), 143.97ppm {–NH–(**C** O)–O–} and 137.46, 136.2, 134.4, 125.94, 125.4, 116.0 ppm (aromatic ring carbons of TDI). TGA thermogram of LFADU has shown four step degradation pattern, at 260 °C (27% weight loss), 360 °C (21% weight loss), 505 °C (40% weight loss), 640 °C (9% weight loss) corresponding to the degradation of urethane, ester, amide and hydrocarbon chains, respectively.

PU from Karanj or *Pongamia glabra* [PGO] oil [PFADU] has also been prepared by similar method. PU obtained from both FAD showed similar structure except for the difference in the structure of pendant fatty amide chains attributed to the variation in the structure of the parent SO chain [33] (Figure 5).

**Figure 5.** Chemical structure of PFADU or NFADU

**Figure 4.** Chemical structure of LFADU.

chains, respectively.

parent SO chain [33] (Figure 5).

The structure of LFADU was established by spectral analyses. FTIR, 1H NMR and 13C NMR spectra showed the presence of the main characteristic absorption bands of parent SO [32]. Along with these bands, additional absorption bands are observed supporting the presence of urethane groups in the backbone of LFADU such as those at 3375cm−1 for hydroxyl groups, 1716.11 cm−1 for urethane carbonyl (str), 1227.56cm−1 for C–N of urethane groups, 1735cm−1 typical for carbonyl (str) of TDI. The characteristic peaks for hydrogen bonded and non‐hydrogen bonded protons of –**H**NCOO– appear at 7.99–7.82ppm and 7.1–6.9ppm, respectively. The aromatic ring protons of TDI occur at 7.5–7.22 ppm. The peaks of – **H**NCOOCH2– are observed at 4.1–3.9ppm and for C**H**3 of TDI appear at 2.25ppm. 13C NMR spectrum also shows the presence of characteristic peaks of LFADU at 17ppm (**C**H3 of TDI), 143.97ppm {–NH–(**C** O)–O–} and 137.46, 136.2, 134.4, 125.94, 125.4, 116.0 ppm (aromatic ring carbons of TDI). TGA thermogram of LFADU has shown four step degradation pattern, at 260 °C (27% weight loss), 360 °C (21% weight loss), 505 °C (40% weight loss), 640 °C (9% weight loss) corresponding to the degradation of urethane, ester, amide and hydrocarbon

PU from Karanj or *Pongamia glabra* [PGO] oil [PFADU] has also been prepared by similar method. PU obtained from both FAD showed similar structure except for the difference in the structure of pendant fatty amide chains attributed to the variation in the structure of the The thermal degradation of PFADU was observed at 177oC and 357oC, with 5% weight loss occurring at 200oC attributed to the entrapped solvent and moisture, 10wt% loss at 225 oC, attributed to the decomposition of urethane moieties, 50wt% and 80wt% losses at 390 oC and 455 oC, respectively, attributed to the degradation of the aromatic ring and aliphatic pendant fatty alkyl chains, respectively.

It was observed that in both LFADU and PFADU, beyond 1.5moles loading of TDI, formation of some lumpy aggregates occurred. Upto 1.5 moles of TDI addition, it is speculated that the isocyanate groups of TDI react with hydroxyl groups of FAD forming PU linkages. Beyond this amount, any additional isocyanate added reacts with the urethane groups of LFADU or PFADU forming allophanate groups (secondary reaction). The final PU attains very high viscosity and crosslinking, so much so that the formation of lumpy aggregates occurs and PU is deprived off its free flowing tendency.

Karak and Dutta have reported the production of PU by amidation and urethanation of methyl ester of *M. Ferrea* or Nahor oil [NO], rich mainly in triglycerides of linoleic, oleic, palmitic and stearic acids. They investigated the structure and physico‐chemical aspects of FADU from NO [NFADU] [26].

## **3.1. PU as coatings**

LFADU has free –OH, –NCO, aliphatic hydrocarbon chains (from parent LO), amide and urethane groups, which make it an excellent candidate for application in protective coatings (Figure 4). LFADU coatings undergo curing at ambient temperature (28‐30oC) by three stage curing phenomenon, (i) solvent evaporation (physical process), (ii) reaction of free –NCO groups of LFADU with atmospheric moisture, and (iii) auto‐oxidation. These coatings show good scratch hardness (2.5kg), impact resistance (200lb/inch), bending ability (1/8inch) and chemical resistance to acid and alkali. PU from PGO [PFADU] has shown moderate antibacterial behavior against *Salmonella* sp. with good scratch hardness (1.9kg), impact resistance (150lb/inch), bending ability (1/8inch), and gloss (46 at 45o) [33]. LFADU coatings have shown superior coating properties than PFADU owing to the fatty acid composition of parent oils (PGO, a non‐drying oil has higher content of oleic acid while LO, a drying oil, is rich in linolenic acid).

Seed Oil Based Polyurethanes: An Insight 417

PFADU showed high activity against *E. coli* (Zone of inhibition: 21‐30 mm) and moderate activity against *S. aureus* (Zone of inhibition: 16‐20 mm). The reason can be the presence of urethane, amide, and hydroxyl groups in the polymer backbone, which can presumably interact with the surface of microbes, causing antibacterial action. B‐PFADU can be used as

In another work, Ahmad and co‐workers developed LFADU hybrid material with tetraethoxy orthosilane [TEOS] as inorganic constituent in the hybrid material [Si LFADU] by in situ silylation of LFAD with TEOS (at 80 ◦C) followed by urethanation with TDI (at room temperature) [35]. Along with the typical absorption bands for LFADU, additional absorption bands were observed at 484 cm−1 (Si–O–Si bending), 795 cm−1 (Si–O–Si sym str) and 1088 cm−1 (Si–O–Si assym str) in FTIR due to the presence of ‐Si–O–Si‐ bond in the hybrid backbone. Hydroxyl value decreases while refractive index and specific gravity increase with the loading of TEOS in Si LFADU, supporting the formation of the hybrid materials by insitu siylation and urethanation reaction. Optical micrograph of Si LFADU

Si LFADU formed hybrid coatings by simple curing route at ambient temperature, over mild steel panels of standard sizes with improved gloss and scratch hardness. SiO2 domains

showed the presence of SiO2 particles surrounded by LFADU (Figure 7).

an antibacterial agent as well as coating material.

**Figure 7.** Optical micrograph of Si LFADU

Karak and Dutta have reported the use of NFADU coatings with very good alkali resistance (Figure 5)[32].
