Synthesis of a series of cyclic oligo(alkylidene isophthalate)s by cyclo-depolymerisation

Hall, Andrew J.; Hodge, Philip; McGrail, C.S.; Rickerby, Jenny

doi:10.1016/s0032-3861(99)00290-6

Cited by 34 publications

(23 citation statements)

References 24 publications

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“…The PHT was obtained in 84% yield with a weight-average molecular weight of 63,000, a T g~1 0 ºC and a T m~1 40 ºC. NMR (CDCl 3 , 300 MHz): δ (ppm) 8 A mixture of cyclic oligomers c(HT) [2][3][4][5] and CL with the selected composition ratio and Sb 2 O 3 (0.5 %-mole), was introduced into a two-necked round-bottom flask equipped with a nitrogen inlet/outlet. The flask was purged with nitrogen to remove all traces of moisture and residual air, and immersed in an oil heating bath.…”

Section: Synthesis Of Cyclic Oligomers C(ht) N By Cyclo-depolymerizatmentioning

confidence: 99%

“…As expected, larger increases in viscosity were attained at higher temperatures. Although the highest viscosity values were achieved with Sb 2 O 3 and Sn(Oct) 2 , polymerization was observed to proceed even in the absence of catalyst upon 8 heating at 200 ºC. In this case, it should be assumed that reaction was activated by catalyst residues used in the cyclo-depolymerization reaction, which were not removed by the used purification procedure.…”

Section: Synthesis Of Pht By Ring-opening Polymerization Of C(ht) Nmentioning

confidence: 99%

“…However, the potential of ROP is strongly constrained by the limited availability of suitable cyclic monomers. Increasing attention is being paid recently to the utilization of cyclic oligoesters as feedstock for the synthesis and processing of aromatic polyesters [3,[7][8][9]. One source of cyclic oligoesters of great interest is cyclo-depolymerization of linear polyesters, which in combination with ROP, would provide an environmentally friendly route for the chemical recycling of currently important thermoplastics as poly(ethylene terephthalate) (PET), poly(butylene terephthalate) (PBT) and other closely related industrial aromatic polyesters and copolyesters [10][11][12][13][14].…”

Section: Introductionmentioning

confidence: 99%

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Poly(hexamethylene terephthalate-co-caprolactone) copolymers: Influence of cycle size on ring-opening polymerization

González-Vidal

Ilarduya

Muñoz‐Guerra

2010

European Polymer Journal

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Poly(hexamethylene terephthalate) was cyclo-depolymerized in solution by heating to yield a fraction of cyclic oligomers of hexamethylene terephthalate (c(HT) 2-5 ) with a content around to 95% in dimer to pentamer. Ring-opening polymerization in the melt of c(HT) 2-5 , either neat or in mixtures with ε-caprolactone (CL) covering a range of HT/CL ratios from 9/1 to 1/9 was carried out to produce polyesters with molecular weights above 30,000 in high yields. The copolyesters had a comonomer composition according to the feed and the microstructure evolved from random to blocky as the content in CL increases. The thermal and mechanical properties of the copolyesters were evaluated for a variety of compositions. Results obtained in this work were compared to those previously obtained by us in the ring-opening copolymerization of CL with a cyclic oligomeric fraction enriched in hexamer and heptamer (c(HT) 6-7 ). Although the polyesters resulting from the use of these two fractions were similar, significant differences were found in polymerization rate evidencing a lower reactivity of c(HT) n with decreasing values of n.

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Section: Synthesis Of Cyclic Oligomers C(ht) N By Cyclo-depolymerizatmentioning

confidence: 99%

Section: Synthesis Of Pht By Ring-opening Polymerization Of C(ht) Nmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Poly(hexamethylene terephthalate-co-caprolactone) copolymers: Influence of cycle size on ring-opening polymerization

González-Vidal

Ilarduya

Muñoz‐Guerra

2010

European Polymer Journal

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“…[9][10][11] Two methods are currently available for the production of the cyclic oligoesters needed for the synthesis of polyesters by ROP, that is, condensation of diols with diacid chlorides and heatinginduced cyclodepolymerization of linear polyesters. [12][13][14][15][16] The latter has become particularly useful for the preparation of alkylene phthalate cyclic oligomers from industrial thermoplastic polyesters like PET, [4,10,11,17] poly(butylene terephthalate), [18,19] and poly(ethylene isophthalate). [20] The procedure, which has been studied in detail by several authors, is based on the ring-chain equilibrium reaction that takes place by heating the polyester at high dilution affording cyclic oligomer fractions in good yields.…”

Section: Introductionmentioning

confidence: 99%

Poly(ethylene‐co‐1,4‐cyclohexylenedimethylene terephthalate) copolyesters obtained by ring opening polymerization

González-Vidal

Ilarduya

Muñoz‐Guerra

2009

J. Polym. Sci. A Polym. Chem.

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Cyclic oligomer fractions of ethylene terephthalate c(ET)n and 1,4-cyclohexylenedimethylene terephthalate c(CT)n were obtained by yclodepolymerization of their respective polyesters, the former containing around 80 mol % of trimer and the latter with around 70 mol % of trimer to pentamer. Mixtures of these fractions at selected compositions were subjected to ring opening copolymerization to give a series of poly(ethylene-cocyclohexylenedimethylene terephthalate) copolyesters with ET/CT comonomer ratios ranging from 90/10 to 10/90. The copolyesters were characterized by GPC and NMR, and their thermal properties were evaluated by DSC and TGA. They had essentially the same composition as the feed from which they were produced and had an average-weight molecular weights between 30,000 and 40,000 g/mol with polydispersities between 2 and 2.7. The distribution of the monomeric units in these copolyesters was essentially at random although it evolved to be a blocky microstructure as the contents in the two comonomers became more dissimilar. Their thermal behavior was the expected one for these types of copolyesters with crystallinity and heating stability decreasing with the content in CT units.

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“…Cyclic ester oligomers have already been known as common by‐products of the polyesterification reactions for many years 1–3. Recently, they have been synthesized also on purpose to be used as feedstocks for environmentally friendly ring‐opening polymerizations and as building blocks for novel polymeric structures 4–6. Nevertheless, cyclic oligomers are undesirable in polyester coatings because they are mobile and tend to migrate to the surface of the coating where they are responsible for hazy surface deposits.…”

mentioning

confidence: 99%

Determination of cyclic polyester oligomers by gel permeation chromatography and matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry

Laine

Österholm

Seläntaus

et al. 2001

Rapid Comm Mass Spectrometry

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Polyesters prepared from adipic acid (AA), phthalic anhydride (PA), isophthalic acid (IPA), terephthalic acid (TPA), and 2-butyl-2-ethyl-1,3-propanediol (BEPD) were investigated by gel permeation chromatography (GPC) and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry(MALDI-TOFMS). All polyesters were found to contain a fraction of low molecular weight molecules that were identified as cyclic ester oligomers. The most abundant cyclic oligomer varied with the diacid used in the synthesis but, in every case, it was either a dimer or a trimer. In addition, the relative amounts of the polyester starting materials influenced the amount of cyclic oligomers formed in the polyesterification reaction. Copyright # 2001 John Wiley & Sons, Ltd.Cyclic ester oligomers have already been known as common by-products of the polyesterification reactions for many years.1±3 Recently, they have been synthesized also on purpose to be used as feedstocks for environmentally friendly ring-opening polymerizations and as building blocks for novel polymeric structures. 4±6 Nevertheless, cyclic oligomers are undesirable in polyester coatings because they are mobile and tend to migrate to the surface of the coating where they are responsible for hazy surface deposits. Studies on the polyester of terephthalic acid (TPA) and 2,2-dimethyl-1,3-propanediol (NPG) have shown that cyclic ester dimers can turn the surface of the polyester whitish when the polyester is stored at temperatures above its glass transition temperature T g . 16±20We were interested in the cyclic oligomers found in polyesters prepared from phthalic acids and diols such as 2-butyl-2-ethyl-1,3-propanediol (BEPD). These polyesters are used in industrially produced coating materials. They exhibit good mechanical properties and are chemically resistant. Commercial polyesters used in coatings often contain as many as four to eight different monomers. The polyesters of our study were prepared from two components, one of four different diacids and one diol at a time. The starting materials of the polyesters were adipic acid (AA), phthalic anhydride (PA), isophthalic acid (IPA), or terephthalic acid (TPA) as diacid and BEPD as diol.We applied GPC and matrix-assisted laser desorption/ ionization time-of-flight mass spectrometry (MALDI-TOFMS) for the characterization of our polyester samples. GPC was used to monitor the polyesterification reactions, while only the final products were analyzed by mass spectrometry. The influence of the diacid used and the diacid/diol ratio on the formation of cyclic oligomers was investigated.

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Synthesis of a series of cyclic oligo(alkylidene isophthalate)s by cyclo-depolymerisation

Cited by 34 publications

References 24 publications

Poly(hexamethylene terephthalate-co-caprolactone) copolymers: Influence of cycle size on ring-opening polymerization

Poly(hexamethylene terephthalate-co-caprolactone) copolymers: Influence of cycle size on ring-opening polymerization

Poly(ethylene‐co‐1,4‐cyclohexylenedimethylene terephthalate) copolyesters obtained by ring opening polymerization

Determination of cyclic polyester oligomers by gel permeation chromatography and matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry

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