Introduction on Crystallization in Multiphase Polymer Systems

Arif, P. Mohammed; Kalarikkal, Nandakumar; Thomas, Sabu

doi:10.1016/b978-0-12-809453-2.00001-3

Cited by 9 publications

(6 citation statements)

References 45 publications

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“…Hadjichristidis et al 54 reported a one-pot synthesis of tetracrystalline tetrablock quarterpolymer poly(ethylene)-bpoly(ethylene oxide)-b-poly(ε-caprolactone)-b-poly(L-lactide) (PE-b-PEO-b-PCL-b-PLLA) from a PE-OH macroinitiator by an organic/organic or organic/metal ″catalyst switch″ strategy. The formation of a tetrablock quarterpolymer was confirmed by 1 H NMR spectroscopy (in liquid and solid state) and gelpermeation chromatography.…”

Section: Introductionmentioning

confidence: 95%

“…Several reviews and many publications have been devoted to these materials due to their versatility and possible applications in several areas, including nanotechnology. 1 − 5…”

Section: Introductionmentioning

confidence: 99%

“…The crystallization of multiphasic block copolymers is a complex process that depends on several variables: segregation strength, composition, molecular weight, and thermal protocol applied during crystallization. Several reviews and many publications have been devoted to these materials due to their versatility and possible applications in several areas, including nanotechnology. − …”

Section: Introductionmentioning

confidence: 99%

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Sequential Crystallization and Multicrystalline Morphology in PE-b-PEO-b-PCL-b-PLLA Tetrablock Quarterpolymers

et al. 2021

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We investigate for the first time the morphology and crystallization of two novel tetrablock quarterpolymers of polyethylene (PE), poly(ethylene oxide) (PEO), poly(ε-caprolactone) (PCL), and poly( l -lactide) (PLLA) with four potentially crystallizable blocks: PE 18 7.1 -b- PEO 37 15.1 -b- PCL 26 10.4 -b- PLLA 19 7.6 (Q1) and PE 29 9.5 -b- PEO 26 8.8 -b- PCL 23 7.6 -b- PLLA 22 7.3 (Q2) (superscripts give number average molecular weights in kg/mol, and subscripts give the composition in wt %). Their synthesis was performed by a combination of polyhomologation (C1 polymerization) and ring-opening polymerization techniques using a ″catalyst-switch″ strategy, either ″organocatalyst/metal catalyst switch″ (Q1 sample, 96% isotactic tetrads) or ″organocatalyst/organocatalyst switch″ (Q2 sample, 84% isotactic tetrads). Their corresponding precursors—triblock terpolymers PE -b- PEO -b- PCL, diblock copolymers PE -b- PEO, and PE homopolymers—were also studied. Cooling and heating rates from the melt at 20 °C/min were employed for most experiments: differential scanning calorimetry (DSC), polarized light optical microscopy (PLOM), in situ small-angle X-ray scattering/wide-angle X-ray scattering (SAXS/WAXS), and atomic force microscopy (AFM). The direct comparison of the results obtained with these different techniques allows the precise identification of the crystallization sequence of the blocks upon cooling from the melt. SAXS indicated that Q1 is melt miscible, while Q2 is weakly segregated in the melt but breaks out during crystallization. According to WAXS and DSC results, the blocks follow a sequence as they crystallize: PLLA first, then PE, then PCL, and finally PEO in the case of the Q1 quarterpolymer; in Q2, the PLLA block is not able to crystallize due to its low isotacticity. Although the temperatures at which the PEO and PCL blocks and the PE and PLLA blocks crystallize overlap, the analysis of the intensity changes measured by WAXS and PLOM experiments allows identifying each of the crystallization processes. The quarterpolymer Q1 remarkably self-assembles during crystallization into tetracrystalline banded spherulites, where four types of different lamellae coexist. Nanostructural features arising upon sequential crystallization are found to have a relevant impact on the mechanical properties. Nanoindentation measurements show that storage modulus and hardness of the Q1 quarterpolymer significantly deviate from those of the stiff PE and PLLA blocks, approaching typical values of compliant PEO and PCL. Results are mainly attribute...

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Section: Introductionmentioning

confidence: 95%

“…Several reviews and many publications have been devoted to these materials due to their versatility and possible applications in several areas, including nanotechnology. 1 − 5…”

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Sequential Crystallization and Multicrystalline Morphology in PE-b-PEO-b-PCL-b-PLLA Tetrablock Quarterpolymers

et al. 2021

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“…Crystallization in block copolymers is a subject widely studied in the past decades [ 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 ]. It is vital to understand the morphology upon crystallization since it is directly related to the final properties of a material.…”

Section: Introductionmentioning

confidence: 99%

“…In addition, many other factors such as composition, molecular weight, crystallization protocol, segregation strength, and block miscibility affect the crystallization behavior. As different morphologies can be developed, the final performance of the materials can be tuned by varying these factors [ 2 , 4 , 7 , 9 , 11 , 15 , 16 , 17 , 18 ].…”

Section: Introductionmentioning

confidence: 99%

Crystallization and Morphology of Triple Crystalline Polyethylene-b-poly(ethylene oxide)-b-poly(ε-caprolactone) PE-b-PEO-b-PCL Triblock Terpolymers

et al. 2021

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The morphology and crystallization behavior of two triblock terpolymers of polymethylene, equivalent to polyethylene (PE), poly (ethylene oxide) (PEO), and poly (ε-caprolactone) (PCL) are studied: PE227.1-b-PEO4615.1-b-PCL3210.4 (T1) and PE379.5-b-PEO348.8-b-PCL297.6 (T2) (superscripts give number average molecular weights in kg/mol and subscripts composition in wt %). The three blocks are potentially crystallizable, and the triple crystalline nature of the samples is investigated. Polyhomologation (C1 polymerization), ring-opening polymerization, and catalyst-switch strategies were combined to synthesize the triblock terpolymers. In addition, the corresponding PE-b-PEO diblock copolymers and PE homopolymers were also analyzed. The crystallization sequence of the blocks was determined via three independent but complementary techniques: differential scanning calorimetry (DSC), in situ SAXS/WAXS (small angle X-ray scattering/wide angle X-ray scattering), and polarized light optical microscopy (PLOM). The two terpolymers (T1 and T2) are weakly phase segregated in the melt according to SAXS. DSC and WAXS results demonstrate that in both triblock terpolymers the crystallization process starts with the PE block, continues with the PCL block, and ends with the PEO block. Hence triple crystalline materials are obtained. The crystallization of the PCL and the PEO block is coincident (i.e., it overlaps); however, WAXS and PLOM experiments can identify both transitions. In addition, PLOM shows a spherulitic morphology for the PE homopolymer and the T1 precursor diblock copolymer, while the other systems appear as non-spherulitic or microspherulitic at the last stage of the crystallization process. The complicated crystallization of tricrystalline triblock terpolymers can only be fully grasped when DSC, WAXS, and PLOM experiments are combined. This knowledge is fundamental to tailor the properties of these complex but fascinating materials.

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Application, Recycling, Environmental and Safety Issues, and Future Prospects of Crystalline Polymer Composites

Cetiner

Baskan‐Bayrak

Okan

2023

Polymer Crystallization

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Introduction on Crystallization in Multiphase Polymer Systems

Cited by 9 publications

References 45 publications

Sequential Crystallization and Multicrystalline Morphology in PE-b-PEO-b-PCL-b-PLLA Tetrablock Quarterpolymers

Sequential Crystallization and Multicrystalline Morphology in PE-b-PEO-b-PCL-b-PLLA Tetrablock Quarterpolymers

Crystallization and Morphology of Triple Crystalline Polyethylene-b-poly(ethylene oxide)-b-poly(ε-caprolactone) PE-b-PEO-b-PCL Triblock Terpolymers

Application, Recycling, Environmental and Safety Issues, and Future Prospects of Crystalline Polymer Composites

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