Infrared Spectroscopy in Analysis of Polymer Crystallinity

Mallapragada, Surya K.; Narasimhan, Balaji

doi:10.1002/9780470027318.a2012

Cited by 19 publications

(18 citation statements)

References 73 publications

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“…This is evident in all Groups, I, II, and III, especially in wet conditions. A possible explanation for this is a reduced mobility of the PEI chains 40 because of the strong ionic interactions acting among hydrated ammonium carbamate moieties. This induced rigidity could be the reason of the limited amine efficiency of PEI-based materials 41 usually between 0.2-0.3 mol of CO 2 /mol of amine, considerably lower than theoretical value of 0.5 in the case of ammonium carbamate formation.…”

Section: Ir Evidence Of Hydrated Carbamate Speciesmentioning

confidence: 99%

CO₂ Capture Partner Molecules in Highly Loaded PEI Sorbents

2017

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Decoupling amine loading from diffusion resistance is one of the main challenges in the development of immobilized amine CO 2 sorbents. Water has been reported to serve this goal, alleviating CO 2 diffusional hindrance in highly loaded amine sorbents. Acting as a mass transport facilitator, water is not the only partner molecule able to enhance bulk CO 2 diffusion. Herein, we show that the enhancing effect of methanol is comparable to that of water in polyethyleniminebased sorbents. Other molecules, such as ethanol, isopropanol, and chloroform, were also examined but did not appear to facilitate CO 2 transport and uptake. Based on a comparison of the Hansen solubility parameters of these molecules, it appears that polarity plays a crucial role in enhancing CO 2 diffusion together with molecular hindrance and hydrogen bonding to a lesser extent.

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Section: Ir Evidence Of Hydrated Carbamate Speciesmentioning

confidence: 99%

CO₂ Capture Partner Molecules in Highly Loaded PEI Sorbents

2017

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“…The characterization by infrared microscope can define the chemical composition and the orientation of the crystalline and noncrystalline phases [17]. Figure 5a shows the IR spectra of VPP, RPP-original, and RPP-extrusion.…”

Section: Crystalline Conformationmentioning

confidence: 99%

“…It can be seen from the peaks in Figure 4 that the crystalline type of RPP-extrusion was similar to the RPP-original, even though the tensile properties were significantly improved. The characterization by infrared microscope can define the chemical composition and the orientation of the crystalline and noncrystalline phases [17]. Figure 5a shows the IR spectra of VPP, RPP-original, and RPP-extrusion.…”

Section: Crystalline Conformationmentioning

confidence: 99%

Development of Tensile Properties and Crystalline Conformation of Recycled Polypropylene by Re-Extrusion Using a Twin-Screw Extruder with an Additional Molten Resin Reservoir Unit

2021

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Plastic mechanical recycling is an attractive method for reducing the amounts of waste plastics. However, the alterations in the mechanical properties (degradation) in recycled plastics is a limitation to the material’s mechanical recycling. In this study, the mechanical recycling was enhanced by the addition of a “molten resin reservoir” unit at the end of the twin-screw extruder. Recycled polypropylene (RPP) obtained from a household was re-extruded with this developed extrusion unit. The tensile properties, type of crystalline, and conformation of polypropylene polymorphs were evaluated and compared for virgin polypropylene (VPP), recycled polypropylene (RPP) without extrusion (RPP-original), and RPP with extrusion by using a new type of extruder (RPP-extrusion). It could be found that the tensile properties of RPP-extrusion were improved, so as to be similar to those of VPP. In addition, the conformation of RPP-extrusion was similar to that of VPP by increasing the ratio between the helix and parallel band. This study succeeded in regenerating the tensile properties and inner structures in recycled PP, which could prolong the used lifetime and decrease the amount of waste from single-use plastic.

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“…In some polymers, certain bands increase in intensity or new bands appear in the IR spectrum as the polymer changes from a crystalline to an amorphous phase or vice versa. The former bands are called amorphous bands and the latter are termed crystalline bands [5]. IR studies are used to observe the appearance of new absorption bands and the weakening or disappearance of certain bands, confirming the phase transformation of nylon 6 iodine complex films.…”

Section: Introductionmentioning

confidence: 99%