On the structure of poly--caprolactams, obtained with bifunctional N-carbamyl derivatives of lactams

Mateva, R.; Petrov, Petar; Rousseva, Sylvia; Dimitrov, R.; Zolova, Genka

doi:10.1016/s0014-3057(99)00132-9

Cited by 21 publications

(20 citation statements)

References 14 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The activated anionic ROP of e-caprolactam is usually started with a two-component catalytic system, consisting of lactam anion or their precursor as an initiator and N-acyllactam-type activator [1,2]. The addition of activators with N-acyllactam structure, such as either monofunctional N-acetyl-e-caprolactam [3][4][5][6][7] and N-benzoyle-caprolactam [8][9][10] or difunctional N,N 0 -isophtaloyl-bis-e-caprolactam [6,10] and N,N 0 -hexamethylene-bis(carbamoyl-e-caprolactam) [11][12][13], is critical for achieving high polymerization rate. This is because of the fact that the nucleophilic attack of the lactam anion on the carbonyl group in the monomer in so-called non-activated ROP of e-caprolactam is considerably slower in comparison with that to the endocyclic carbonyl group in the activator [1,2].…”

Section: Introductionmentioning

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%

See 1 more Smart Citation

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

et al. 2011

View full text Add to dashboard Cite

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.

show abstract

Section: Introductionmentioning

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

View full text Add to dashboard Cite

show abstract

“…The voltage and current of Cu Kα X-ray source were 30 kV and 16 mA respectively. Percentage crystallinity by XRD was calculated by a standard procedure [21].…”

Section: Characterizationmentioning

confidence: 99%

“…The important difference between these two structures is that the chain-axis repeat is 1.724 nm in the α form due to its extended planar conformation and for γ form; it is 1.688 nm due to twisted helical transformation. The β form is said to be the variant of γ form in which the chains have disordered conformation with no definite chirality and chain-axis repeat of this phase is 1.67 nm [19,21,22]. The α, β and γ crystalline forms can be detected by FT-IR method.…”

Section: A Morphological Featuresmentioning

confidence: 99%

Structure and mechanical behaviors of thermoplastic polyurethane thin film coated polyamide 6 fibers part II. A solution coating method

John

Furukawa

2012

J Polym Res

View full text Add to dashboard Cite

Thermoplastic polyurethane thin film (TPU) coated PA6 fibers were prepared by dipping fibers into a TPU solution. The thickness of the thin film coating was 20 μ m. A series of polymer glycols which include polycarbonate, polyether and polyester were used for the preparation of the TPU. Both tensile strength and elongation at break of the TPU coated fibers increased although both magnitudes of the TPUs are much lower than for the original PA6 fibers. Also there was a significant improvement in the abrasion resistance TPU coated PA6 fibers. The PA6 fibers are prone to micro-cracks when under mechanical stress but the TPU thin film coating delayed the formation of the micro-cracks, thereby improving the mechanical properties of PA6 fibers. The theoretical investigation on the effect of interface interaction region using the viscous flow model described could clearly explain the effect of the same on the mechanical performance of TPU coated PA6 fibers.

show abstract

“…This may be explained by two reasons: firstly, the increase in activator concentration result in the increase in polymerisation rate, thus the heat release from polymerisation may interact on the crystal growth. Secondly, the increase in activator concentration shorted the polymer chain length due to the adding of more starting point for polymer chain growth [51], the formation of hydrogen bounds within the polymer chains is thus more difficult, which decrease final degree of crystallinity.…”

Section: C1 Concentration Effectmentioning

confidence: 99%

Anionic polymerisation of caprolactam: process monitoring and reaction kinetic studies

Yang¹

View full text Add to dashboard Cite

Reactive processing of PA6 (in-situ anionic polymerization of caprolactam-APCL) enables the production of high performance composite with high mechanical property, good weldability, and recyclability for structural, aerospace and automotive applications.Compare to melt processing, reactive processing enables shorter cycle time, lower processing temperature and pressure. This makes reactive processing a promising new manufacturing technique capable of addressing mass markets.Unfortunately, the insufficient study on influences of processing conditions and reaction kinetics have limited the commercial implementation of the reactive system. This work aims to investigate the processing parameter effect on polymer properties and validate the reaction kinetic models of small scale isothermal polymerization. Experiments were carried out using Differential Scanning Calorimetry (DSC) for the in-situ monitoring of polymerization and crystallization under different processing conditions. Results show that the increase in initiator, activator concentration and polymerization temperature lead to the increase in reaction rate and drop in crystallinity. Whilst this behaviour was expected, the research also shows that the polymer conversion exhibits a far more complex behaviour. For low temperatures, it appears that the monomer conversion is inhibited by early crystallisation whereas for high temperatures the reaction equilibrium shifts towards the monomer state.The derived polymerisation and crystallisation heat flows were used for validation of kinetic models including Kamal-Sourour and Malkin model for polymerisation, Kim model for crystallisation. All experiment data support the validity of Kamal-Sourour model in describing the kinetic development of polymerisation reaction using C1-C20P catalyst system. With the parameters identified from this work, Kamal-Sourour model accurately predict the polymerisation rate under different processing conditions. On the contrast, Malkin polymerisation model failed to give meaningful modelling of the same process. Though Kim crystallisation model gave excellent simulation of the crystallisation process during APCL, the physical meaning of parameter is yet to be determined.

show abstract

On the structure of poly--caprolactams, obtained with bifunctional N-carbamyl derivatives of lactams

Cited by 21 publications

References 14 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

Structure and mechanical behaviors of thermoplastic polyurethane thin film coated polyamide 6 fibers part II. A solution coating method

Anionic polymerisation of caprolactam: process monitoring and reaction kinetic studies

Contact Info

Product

Resources

About