The Raman spectra of oriented isotactic polypropylene

Báez, M Arruebarrena de; Hendra, P.J.; Judkins, M.

doi:10.1016/0584-8539(95)01512-1

Cited by 108 publications

(53 citation statements)

References 11 publications

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“…The two new peaks of the nonwoven samples come from the PET core. [23,24,26] These results reveal that the PET core had been exposed to some extent after the thermal bonding process, and the degree of exposure increased with increasing thermal bonding temperature, bonding time and thermal conductivity of the mould material.…”

Section: Characterization Of Fibre Morphology and Structurementioning

confidence: 75%

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Morphology and Structure of Constituent Fibres in Thermally Bonded Nonwovens

Wang¹,

Gong²

2006

Macro Materials & Eng

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Summary: A new process has been developed to produce three‐dimensional nonwovens directly from staple fibres. In order to establish suitable windows of the process parameters to achieve high‐quality nonwoven products, the effects of thermal bonding temperature, dwell time and mould material on the morphology and structure of the fibre have been investigated using PP/PET bi‐component fibres. It was evident from both scanning electron microscope images and Raman spectra that thermal‐induced shrinkage of the PP sheath fibre occurred in the thermal bonding process, leading to deformation and cracking of the PP sheath and exposure of the PET core. X‐ray diffraction results revealed crystal imperfection and/or less ordered polymer chains, more γ‐form and thermal contraction of the crystal lattice for the PP sheath fibre, while birefringence measurements indicated that both the birefringence and the orientation factor for the PP fibre decreased after the thermal bonding process. The degrees of the thermal‐induced shrinkage increased, and the crystallinity, birefringence and orientation factor of the PP sheath fibre decreased with increasing thermal bonding temperature, dwell time and thermal conductivity of the mould material. All these can be attributed to the different levels of modification of chemical composition caused by thermal oxidative degradation and thermal‐induced relaxation of the orientation during the thermal bonding process.Changes of morphology and crystalline features of PP/PET fibre after thermal bonding process.imageChanges of morphology and crystalline features of PP/PET fibre after thermal bonding process.

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Section: Characterization Of Fibre Morphology and Structurementioning

confidence: 75%

“…Average values from the 20 repetitions were used for further calculation. Then the birefringence was calculated by: [23,24] Dn…”

Section: Characterization Of Fibre Morphology and Structurementioning

confidence: 99%

Morphology and Structure of Constituent Fibres in Thermally Bonded Nonwovens

Wang¹,

Gong²

2006

Macro Materials & Eng

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“…Although polarization of precursor spectra is very poor, spectra of 500% stretched single fibre show a highly polarized fibre, according to a high orientation of the PP chain along the fibre axis. Nielsen et al and Arrueberra de Baez [35][36] have assigned the ~810 [r CH2 + ν C-C ] and [r CH2 ] ~840 cm -1 peaks to crystalline long and shorter helical chains, respectively. Thus a measure of the crystallinity/axial orientation of the chains can be made from the area ratio of these two bands for the two different polarization: n 1 =[A 841 /A 808 ] // / [A 841 /A 808 ] ⊥ = 1.5 in the precursor to 1.7 in the x 500 % stretched single fibre).…”

Section: Choice Of the Raman Probesmentioning

confidence: 99%

Micro-Raman study of the fatigue and fracture behaviour of single PA66 fibres: Comparison with single PET and PP fibres

Colomban

Ramirez

Paquin

et al. 2006

Engineering Fracture Mechanics

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“…Figure 2 depicts the Raman spectra between 500 and 1450 cm −1 for each stage in the solid support fabrication process. Spectrum 1 is typical for ungrafted polypropylene, with the peaks observed being consistent with isotactic polypropylene 12. Spectrum 2 shows the peaks for the PS‐ graft ‐PP, which are consistent with mono‐substituted phenyl groups from the polystyrene observed13 at 1000 and 620 cm −1 .…”

Section: Resultsmentioning

confidence: 99%

Applications of Multicomponent Reactions to the Synthesis of Diverse Heterocyclic Scaffolds

Sunderhaus

Martin

2009

Chemistry A European J

694

174

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The sequencing of multicomponent reactions (MCRs) and subsequent cyclization reactions is a powerful stratagem for the rapid synthesis of diverse heterocyclic scaffolds. The optimal MCR is sufficiently flexible that it can be employed to generate adducts bearing a variety of functional groups that may then be selectively paired to enable different cyclization manifolds, thereby leading to a diverse collection of products. The growing interest in diversity-oriented synthesis has led to increased attention to this paradigm for library synthesis, which has inspired many advances in the design and implementation of MCRs for the construction of diverse heterocyclic scaffolds.

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The Raman spectra of oriented isotactic polypropylene

Cited by 108 publications

References 11 publications

Morphology and Structure of Constituent Fibres in Thermally Bonded Nonwovens

Morphology and Structure of Constituent Fibres in Thermally Bonded Nonwovens

Micro-Raman study of the fatigue and fracture behaviour of single PA66 fibres: Comparison with single PET and PP fibres

Applications of Multicomponent Reactions to the Synthesis of Diverse Heterocyclic Scaffolds

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