Synthesis and thermal properties of [n]-polyurethanes

Take-down policy If you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim.Downloaded from the University of Groningen/UMCG research database (Pure): http://www.rug.nl/research/portal. For technical reasons the number of authors shown on this cover page is limited to 10 maximum. AbstractAlternating poly(amide urethane)s from 1-caprolactam, amino alcohols H 2 N -(CH 2 ) x -OH ðx ¼ 2 -6Þ; and diphenyl carbonate were prepared by polycondensation of a-hydroxy-v-O-phenylurethanes 4a-e. The degree of oligomerization was adjusted by the conversion. Oligomers with two or three O-phenylurethane end groups and predetermined molecular weight were prepared by polycondensation of the a-hydroxy-v-O-phenylurethanes 4a-e in the presence of comonomers with O-phenylurethane end groups in a given concentration. In order to prepare oligomers with hydroxyl and carboxyl groups at both chain ends suitable for coupling reactions, chain analogous reactions were performed with amino acids and amino alcohols. The microstructure of the polymers and the nature of end groups was determined by means of 1 H NMR spectroscopy and the molecular weights were determined by means of gel permeation chromatography. The poly(amide urethane)s 5a-e prepared are semicrystalline materials with melting points between 150 and 200 8C. q

show abstract

“…7). This observation was made earlier in the series of [n ]-polyamides, [n ]-polyurethanes [8], and [n ]-poly(ester amide)s [14,15]. …”

Section: Thermal Propertiessupporting

confidence: 65%

Textural properties of poly(glycidyl methacrylate): acid-modified bentonite nanocomposites

et al. 2013

View full text Add to dashboard Cite

show abstract

“…These observations were also made for [n]-polyurethanes. [15] Furthermore, the spectrum reveals an almost 1:1 ratio of TeU and PC repeating units, although an initial three-fold excess of PC was used. The small difference in the 1:1 ratio of TeU and PC repeating units is caused by the unavoidable formation of TeU-TeU diads (d …”

Section: Copolymerization Of Teu With Ec or Pcmentioning

confidence: 99%

“…This observation is even more clear upon a second heating. Furthermore, Table 2 shows that the degree of crystallinity (first heating) decreases continuously for polyurethanes [14][15][16][17][18][19] in which the PC content increases from 19.6 to 54.2 mol-%. This is because of the increasing content of atactic repeating units in the polyurethane.…”

Section: Thermal Propertiesmentioning

confidence: 99%

“…Upon a second heating, the polyurethanes show a melting transition at a lower temperature and with a lower melting enthalpy than upon first heating, indicating that smaller crystals and a lower degree of crystallinity is obtained from the melt. Figure 7 shows that there is a continuous decrease of T m from 196.1 to 167.5 8C (first heating) for polyurethanes [14][15][16][17][18][19] in which the PC content increases from 19.6 to 54.2 mol-% indicating a rather random copolymer structure. Furthermore, DSC data support the results of the calculation of the PC content in polyurethanes 14 and 15 compared with 20 and 21.…”

Section: Thermal Propertiesmentioning

confidence: 99%

See 1 more Smart Citation

Copolymerization of Ethylene Carbonate and 1,2‐Propylene Carbonate with Tetramethylene Urea and Characterization of the Polyurethanes

Ubaghs¹,

Novi²,

Keul³

et al. 2004

Macro Chemistry & Physics

Self Cite

View full text Add to dashboard Cite

Summary: Tetramethylene urea (TeU, 1) is successfully copolymerized with 1,2‐propylene carbonate (PC, 2) leading to a polyurethane ($\overline M _{\rm n}$ = 12 200; $\overline M _{\rm w}$ 18 400; $\overline M _{\rm w} /\overline M _{\rm n}$ = 1.50) with a Tm of 145.7 °C and a Tg of 53.7 °C. Mechanistic studies with a blocked isocyanate model compound revealed that, at no stage of the reaction is the TeU ring opened to form an isocyanate. Hence, a well‐underlined mechanism for the copolymerization is proposed. Furthermore, TeU is successfully copolymerized with mixtures of PC and ethylene carbonate (EC, 3). From NMR spectroscopic data of the polyurethanes obtained, it is concluded that PC is less reactive than EC. However, it is possible to increase the PC content in poly(TeU‐EC‐stat‐TeU‐PC) by increasing the PC/EC ratio in the feed. 13C NMR spectroscopy reveals that a random copolymer is obtained. This conclusion is supported by differential scanning calorimetry (DSC) data, which show a continuous decrease in Tm with increasing PC content.Tm was found to decrease with increasing PC content.imageTm was found to decrease with increasing PC content.

show abstract

“…Fey et al reported the same behavior for poly(ester amide)s [27,28] and polyurethanes. [29,30] In addition to this odd/even effect, the T m of PEU (x,y,4) increased with the proportion of the diurethane moiety in the polymer chain (entries 1, 3 and 5 in Table 1).…”

Section: Thermal Properties Of Peu (Xyz)mentioning

confidence: 96%

Synthesis and Chemical Recycling of Novel Poly(ester‐urethane)s Using an Enzyme

Soeda¹,

Toshima²,

Matsumura³

2005

Macromolecular Bioscience

View full text Add to dashboard Cite

A series of enzymatically recyclable poly(ester-urethane)s consisting of a biodegradable diurethane moiety as a hard segment and an ester moiety as an enzymatically cleavable linkage was chemo-enzymatically prepared by two routes. The poly(ester-urethane) was prepared by a) the ring-opening polymerization of a cyclic ester-urethane monomer synthesized via the transesterification reaction of biodegradable diurethanediol and dicarboxylate ester using lipase and b) the direct polycondensation of a diurethanediol and a dicarboxylate ester. A significantly higher molecular-weight poly(ester-urethane) having the highest molecular weight (Mw) of 101,000 was produced by the ring-opening polymerization of the cyclic ester-urethane monomer when compared with that produced by the polycondensation of the dicarboxylate ester with diurethanediol. The poly(ester-urethane) was readily degraded by lipase into the corresponding cyclic oligomers; the oligomers were readily repolymerized by the ring-opening polymerization using lipase for chemical recycling.

show abstract

Synthesis and thermal properties of [n]-polyurethanes

Cited by 52 publications

References 6 publications

Textural properties of poly(glycidyl methacrylate): acid-modified bentonite nanocomposites

Textural properties of poly(glycidyl methacrylate): acid-modified bentonite nanocomposites

Copolymerization of Ethylene Carbonate and 1,2‐Propylene Carbonate with Tetramethylene Urea and Characterization of the Polyurethanes

Synthesis and Chemical Recycling of Novel Poly(ester‐urethane)s Using an Enzyme

Contact Info

Product

Resources

About