Toughening mechanism in impact polypropylene copolymer containing a β-nucleating agent

Qiu, Biwei; Chen, Feng; Shangguan, Yonggang; Lin, Yu; Zheng, Qiang; Wang, Xia

doi:10.1039/c6ra01046f

Cited by 11 publications

(10 citation statements)

References 48 publications

(72 reference statements)

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“…This agrees with the enhanced impact strength of BE0 (or CBE0) at 20°C, compared with pure iPP (or CE0), as shown in Figure . The similar phenomenon has also been reported in the work of Qiu et al The presence of CNTs seems to hardly change the mobility of the iPP molecular chains.…”

Section: Resultssupporting

confidence: 87%

“…Generally, the addition of elastomers or rubbers into the iPP matrix would enhance the molecular chains mobility of the amorphous phase in iPP blends. Since the fracture resistance is the substantial response of the molecular chain mobility, the enhanced of the molecular chain mobility signifies the higher dissipation of impact energy, and finally results in the significant enhancement of the impact properties of the iPP/elastormer or rubber blends. In our previous work, we studied the effect of a series of elastomers like styrene butadiene styrene block polymer, strene‐ethylele‐butadiene‐styrene block copolymer, and polyolefin elastomer on the toughness of iPP with CNTs and β‐NAs .…”

Section: Resultsmentioning

confidence: 99%

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Great improvement of low‐temperature impact resistance of isotactic polypropylene/ethylene propylene diene monomer rubber blends by traces of carbon nanotubes and β‐nucleating agents

Fan

Zhang

et al. 2019

Polymers for Advanced Techs

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In this work, a considerable low-temperature toughness enhancement of isotactic polypropylene (iPP) was achieved by adding 30 wt% ethylene propylene diene monomer rubber (EPDM) as well as traces of β-nucleating agent (β-NAs) and carbon nanotubes (CNTs). The impact strength of the iPP/30 wt% EPDM blend with 0.1 wt% β-NAs reached 6.57 kJ/m 2 at −20°C, over 2.5 times of pure iPP. A slightly improved impact strength was further found in the β-nucleated iPP/30 wt% EPDM at the presence of 0.05 wt% CNTs. The presence of traces of CNTs, β-NAs, and EPDM displayed synergistic low-temperature toughness reinforcement effect on the iPP blends. The underlying toughening mechanism was attributed to the formation of a great amount of voids and plastic deformation of iPP matrix affected by CNTs, β-NAs, and EPDM.Our work provided a feasible strategy to significantly increase the low-temperature toughness of iPP. methods. The addition of β-nucleating agents (β-NAs) proved to be the most effective method to induce many β-crystals in iPP. Copious amounts of studies have revealed that the introduction of β-NAs can only significantly improve the room-temperature toughness of iPP. 12-15 For instance, Grein et al 16 found that the sole addition of β-NAs was insufficient to enhance the low-temperature toughness of iPP, and the fracture behavior is susceptible to the crystalline structure only when the test temperature exceeded the glass transition temperature. Likewise, the tensile strength and modulus of β-iPP were also deteriorated, due to the loosely stacking crystal structure of β-crystals. The rigid nanofillers like calcium carbonate (CaCO 3 ) and carbon nanotubes (CNTs) were usually acted as the reinforcement fillers for polymers. 17-20 Liu et al 21 observed that the tensile strength and Young's modulus of iPP/CNT nanocomposites with 3 wt% CNTs were improved by 72 and 37%, respectively, as compared with pure iPP. Interestingly, the rigid nanofillers also showed the potential to enhance the impact toughness of iPP. Wang et al 22 reported that iPP nanocomposites with 0.5 wt% CNTs demonstrated the improved impact strength by 27% compared with the pure iPP. As a matter of fact, either one aforementioned factors is not enough to significantly improve the low-temperature toughness of iPP. Thus, a few studies were carried out to incorporate two of above factors. Kotek et al 23 investigated the synergistic effect of ethylenepropylene copolymer (EPR) and β-NAs on the low-temperature toughness of iPP and found that the elongation at break of the β-nucleated iPP/EPR blends was increased by 121% at a low temperature (−40°C). Hu et al 24 observed that the iPP blends containing β-NAs and ethylene-octene copolymer exhibited excellent low-temperature impact toughness compared with pure iPP and revealed the combined effects of matrix crystalline structure and the amorphous chain mobility on the low-temperature toughness of the blends. Nonetheless, there are only a few publication focused on the low-temperature toughness of iPP, not even to mention t...

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Section: Resultssupporting

confidence: 87%

Section: Resultsmentioning

confidence: 99%

Great improvement of low‐temperature impact resistance of isotactic polypropylene/ethylene propylene diene monomer rubber blends by traces of carbon nanotubes and β‐nucleating agents

Fan

Zhang

et al. 2019

Polymers for Advanced Techs

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“…It was revealled that the PP could only form α‐crystals in this condition. For β‐nucleated samples, an obvious new diffraction peak at 16.3 ° were observed, corresponding to the (300) crystal plane of β‐crystals . It was suggested that the formation of abundant β‐crystals in PP matrix, supported by large X β and K β values (listed in Table ) after β‐modification.…”

Section: Resultsmentioning

confidence: 96%

“…The K β was calculated according to (Equation ) . The crystallinity of β‐crystal (X β ) and α‐crystal (X α ) were obtained from the Equations and , respectively

X_{c} = \frac{\sum {normalA}_{cryst}}{\sum {normalA}_{cryst} + \sum {normalA}_{amorp}}

{normalK}_{β} = \frac{{normalA}_{β} (300)}{{normalA}_{β} (300) + {normalA}_{α} (110) + {normalA}_{α} (040) + {normalA}_{α} (130)}

{normalX}_{β} = {normalX}_{normalc} \times {normalK}_{β}

{normalX}_{α} = {normalX}_{normalc} ‐ {normalX}_{β}

…”

Section: Methodsmentioning

confidence: 99%

“…Annealing treatment at elevated temperature between glass transition temperature ( T g ) and melting temperature ( T m ) also is an effective way to toughen β‐iPP and enhance its strength and modulus simultaneously. The improvement of strength and modulus are mainly attributed to the enhanced overall crystallinity and improved crystal structure (thickened lamellae thickness) caused by the secondary crystallization . Among, the impact strength of PP could be remarkably enhanced after annealing at optimum temperature around 130°C .…”

Section: Introductionmentioning

confidence: 99%

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Improving the impact strength of polypropylene/carbon fiber composites via β‐modification and annealing treatment

Liu

Yuan

Fang

et al. 2018

Polymer Crystallization

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The low impact strength of short carbon fiber (CF) reinforced polypropylene (PP) composites (PP/CF) restricts their practical application. Many studies focus on improving interfacial adhesion strength between PP and CF, while the essential properties of PP matrix are also significant, but rarely investigated for toughening PP/CF composites. In this work, the combination of β‐modification and annealing treatment were adopted to modify the intrinsic toughness of PP matrix, thereby enhancing the impact strength of PP/CF composites, meanwhile their flexural strength and modulus were almost maintained. From the XRD, DSC, POM, DMA and SAXS results, we observed that abundant β‐crystals with small size were produced in PP matrix after β‐modification. In addition, increased overall crystallinity, perfected crystals structure and looser amorphous region were generated after annealing treatment. These microstructure changes resulting from β‐modification and annealing treatment, together triggered the plastic deformation of PP matrix, which was the main reason for toughening PP/CF composites.

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Effect of isotactic polypropylene on crystal structure and morphology of β-modified random copolymerized polypropylene

et al. 2017

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Toughening mechanism in impact polypropylene copolymer containing a β-nucleating agent

Abstract: The voids in β-nucleated IPC could help to ease craze formation and multiply shear yielding while extensive stress whitening phenomenon appears in neat IPC.

Cited by 11 publications

References 48 publications

Great improvement of low‐temperature impact resistance of isotactic polypropylene/ethylene propylene diene monomer rubber blends by traces of carbon nanotubes and β‐nucleating agents

Great improvement of low‐temperature impact resistance of isotactic polypropylene/ethylene propylene diene monomer rubber blends by traces of carbon nanotubes and β‐nucleating agents

Improving the impact strength of polypropylene/carbon fiber composites via β‐modification and annealing treatment

Effect of isotactic polypropylene on crystal structure and morphology of β-modified random copolymerized polypropylene

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