Anionic polymerization of ε-caprolactam in the presence of symmetrically substituted ureas

Marelová, Jana; Roda, Jan; Stehlı́ček, J.

doi:10.1016/s0014-3057(98)00101-3

Cited by 12 publications

(13 citation statements)

References 16 publications

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“…S2) are linear at least up to 80-85% of the monomer conversion indicating that the polymerization of e-caprolactam exhibits zero-order kinetics in respect of the monomer concentration under investigated conditions. According to [15,16,23], the rate of activated anionic polymerization of e-caprolactam exhibiting zero-order kinetics could be expressed by following equations: As shown in Fig. 2, the zero-order plots are linear up to high monomer conversions (80-85%) and pass trough the origin.…”

Section: Mg/mgcl 2 As Initiatormentioning

confidence: 99%

“…Sodium salt of e-caprolactam (CLNa) or its precursors (sodium hydride, sodium methoxide) are a most used initiator in the (co)polymerization of lactams [7,9,[11][12][13][14][15][16][17]. The main disadvantages of this initiator are rather high content of cyclic oligomers [18][19][20] in obtained polymers and relatively low thermal stability [5] of resulting polyamides.…”

Section: Introductionmentioning

confidence: 99%

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Activated anionic ring-opening polymerization of ε-caprolactam with magnesium di(ε-caprolactamate) as initiator: effect of magnesium halides

et al. 2011

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The activated anionic ring-opening polymerization of e-caprolactam initiated by 0.35 mol% of combined initiator, i.e., equimolar mixture of magnesium di(e-caprolactamate) (CL 2 Mg) with magnesium halides (MgCl 2 , MgBr 2 , and MgI 2 ) as well as of e-caprolactam magnesium bromide (CLMgBr) in the presence of 0.35 mol% of N-acetyl-e-caprolactam as an activator has been investigated in the temperature range 140-200°C. It was found that the reaction rate increased while the apparent activation energy decreased in the following series: CL 2 Mg/ MgCl 2 \ CL 2 Mg/MgBr 2 * CLMgBr \ CL 2 Mg/MgI 2 . In addition, the poly(ecaprolactam)s prepared with CL 2 Mg/MgX 2 (MgX 2 = MgCl 2 , MgBr 2 , and MgI 2 ) are characterized by slightly higher thermal stability than polymers obtained with CLMgBr as initiator. These observations were explained in terms of the coordination of Lewis acids (MgX 2 , where X = Cl, Br, and I) with imide carbonyl of N-acyllactam end groups leading to the increase of their reactivity and stability.

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Section: Mg/mgcl 2 As Initiatormentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Activated anionic ring-opening polymerization of ε-caprolactam with magnesium di(ε-caprolactamate) as initiator: effect of magnesium halides

et al. 2011

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“…Various methods have been proposed to determine the conversion of CL. They include gravimetry,3, 12, 13, 18–27 gas chromatography,28, 29 enthalpy of polymerization,4, 30 and in‐line infrared spectroscopy 31. Among them, the gravimetry is used the most.…”

Section: Introductionmentioning

confidence: 99%

Anionic polymerization of lactams: A comparative study on various methods of measuring the conversion of ε‐caprolactam to polyamide 6

Zhang

2006

J of Applied Polymer Sci

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Anionic ring-opening polymerization of lactams leads to the formation of poly(lactams) or polyamides. This work aimed at comparing the performance of four methods for measuring the conversion of -caprolactam (CL) to polyamide 6. The latter was either a homopolymer (PA6) or grafts onto polystyrene (PS-g-PA6 graft copolymer). Those four methods were mass balance based on solvent extraction (methanol, water, THF, or acetone), mass balance based on vacuum drying at 140°C, thermogravimetric analysis (TGA), and elemental analysis based on nitrogen. The mass balances based on methanol extraction and vacuum drying at 140°C and TGA were all suitable for measuring the conversion of CL, whether the resulting polymer was the PA6 or PS-g-PA6. The mass balance based on water extraction was good for the PA6 and not good for the PS-g-PA6. The elemental analysis based on nitrogen was not suitable for the PA6 nor for the PS-g-PA6.

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“…As shown in Figure 2(b), the majority of ACCL absorption bands are those corresponding to NÀ ÀH (3335, 3455, 1535), C¼ ¼O (1648), and C¼ ¼C (1395, 844 cm 21 ). For PS-CCL, the bands of NÀ ÀH and C¼ ¼O appear, but those of C¼ ¼C disappear; furthermore, it shows all the characteristic bands due to polystyrene, i.e., b(CH) at 1458, g(CC) at 1100, and g(CH) at 690 cm 21 . Thus, FTIR analysis suggests the formation of PS-CCL macroactivator by free radical copolymerization of styrene and ACCL.…”

Section: Macroactivator Synthesismentioning

confidence: 97%

“…The polymerization takes place in a few minutes because of the much lower activating energy for the initial nucleophilic attack of caprolactam anion on the CCL group. Isophthaloyl-biscaprolactam, 20 N-carbamoyl-caprolactam 21 and other low molecular weight activators containing CCL group (microactivators) were also reported. 22 The addition of PS-CCL in this study resulted in a polymerization time of less than 20 min.…”

Section: Graft Copolymer Synthesismentioning

confidence: 99%

Preparation of PS‐g‐PA6 copolymers by anionic polymerization of ε‐caprolactam using PS precursors with N‐carbamated caprolactam pendants as macroactivators

Liu

Xiong

et al. 2008

J of Applied Polymer Sci

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ABSTRACT:The graft copolymer of polystyrene and polyamide 6 (PS-g-PA6) was investigated by anionic polymerization of e-caprolactam (CL), using the free radical copolymer of styrene and a kind of allyl monomer containing N-carbamated caprolactam group as macroactivator (PS-CCL). CL monomers were grafted onto PS-CCL backbone via initiating N-carbamated caprolactam (CCL) pendants along its backbone to form the graft copolymer in the presence of catalyst sodium caprolactamate. The macroactivator was characterized by Fourier-transform infrared spectroscopy and nuclear magnetic resonance, and the graft copolymer by the selective solvent extraction technique using methanol and chloroform as solvents. PS-g-PA6 copolymers with different PS content were synthesized to study the effect of PS on morphology, crystallinity, dimensional stability, and thermal properties, using scanning electron microscopy, X-ray diffraction, water absorption measurement, thermogravimetric analysis, and differential scanning calorimetry. The results show the percentage crystallinity of graft copolymer decreases with increasing PS content, but the addition of PS scarcely influences the crystalline structure of PA6. The graft copolymer has improved thermal properties and dimensional stability.

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Anionic polymerization of ε-caprolactam in the presence of symmetrically substituted ureas

Cited by 12 publications

References 16 publications

Activated anionic ring-opening polymerization of ε-caprolactam with magnesium di(ε-caprolactamate) as initiator: effect of magnesium halides

Activated anionic ring-opening polymerization of ε-caprolactam with magnesium di(ε-caprolactamate) as initiator: effect of magnesium halides

Anionic polymerization of lactams: A comparative study on various methods of measuring the conversion of ε‐caprolactam to polyamide 6

Preparation of PS‐g‐PA6 copolymers by anionic polymerization of ε‐caprolactam using PS precursors with N‐carbamated caprolactam pendants as macroactivators

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