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A novel effective way of comprising a β-nucleating agent in isotactic …

For inducing β-crystallization in i-PP by using β-nucleating agent, the effect of the amount of the nucleating agent is very delicate.Sterzynski et al. studied the nucleation efficiency of i-PP nucleated with a β-nucleating agent of Permanent Red E3B thoroughly.It was found that a maximum of k-value was obtained for a concentration of 5 × 10 −5 wt% …

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Insight into the negative Poisson's ratio effect of metallic …

This paper presented a detailed study of the negative Poisson's ratio (NPR) effect on shrinkage deformation and crushing stress of metallic auxetic reentrant honeycomb under low, medium and high-velocity compressions. Instead of the traditional calculating method for the crushing stress of auxetic honeycomb, the new theoretical …

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PP (isotactic): Polypropylene

Glass Transition Temperature The glass transition is one of the most important properties of amorphous and semi-crystalline materials, e.g., inorganic glasses, amorphous metals, polymers, pharmaceuticals and …

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Cryogenic crushing of polystyrene

Abstract Atactic and isotactic polystyrene powders were fractured with a ball mill at −196°C. The molecular weight distributions at various milling times measured by GPC show an initial asymmetric ...

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Direct melt-crystallization of isotactic poly-1-butene with …

In-situ high-pressure FTIR was applied to detect the crystal modification change during the non-isothermal melt-crystallization process of isotactic poly-1-butene (iPB-1) in atmospheric N 2 and high-pressure CO 2 at the cooling rate of 1 °C/min. Under atmospheric N 2 and low-pressure CO 2, e.g., 6 MPa CO 2, the characteristic band at …

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Axial quasi-static crushing of composite tubes: An …

Crushing morphologies of simulations using flat rigid platens of various mesh geometries proves that mesh structure of the top surface has a considerable effect on the simulated crushing behavior of the composite tubes. Local buckling behavior observed in the tube walls, in addition to splaying modes and vertical tears. ...

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Enhanced Mechanical Toughness of Isotactic Polypropylene …

Herein, we report the use of bulk molybdenum disulfide (MoS 2) as the reinforcing agent to enhance the toughness of isotactic polypropylene (iPP).The iPP-MoS 2 nanocomposites with varying amounts of MoS 2 (0.1 to 5 wt %) were prepared by a one-step melt extrusion method, and the effects of MoS 2 on the morphology, thermal, and …

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Isolating the Effect of Crosslink Densities on Mechanical …

Given the importance of preserving the mechanical properties of recycled isotactic polypropylene (iPP) during its processing, this work provides an improved understanding of the contribution of introducing physical or chemical crosslinks using the dissipative particle dynamics (DPD) method, which makes it possible to model iPP …

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A Library Synthesis of Highly Isotactic Polyacrylamides with …

The tacticity of vinyl polymers, i.e., the regularity of the side-chain stereochemistry, plays a crucial role in determining their physical properties. For …

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Influence of compounded α/β-nucleating agents on the

TMB-5 of the aromatic diamides and WBG-II of the rare earth compound were employed as β-nucleating agents in conjunction with three commercially available α-nucleating agents MDBS, TMP-6 and HPN-68L, and the nucleating effects of compounded α/β-nucleating agents in isotactic polypropylene (iPP) were investigated. The …

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Photooxidative degradation and fragmentation behaviors of …

The photooxidative degradation and fragmentation behaviors of isotactic polypropylene (itPP) were simulated in laboratory after various postconditions, such as …

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Analysis of Crushing of Granular Material Under Isotropic and Biaxial

Analysis of Crushing of Granular Material Under Isotropic and Biaxial Stress Conditions Sebastian Lobo-Guerrero, Graduate Student 1 [email protected] Luis E. Vallejo, Professor 2 [email protected] 1 Department of Civil and Environmental Engineering, University of Pittsburgh, Pittsburgh, PA 15261, USA. Department of Civil and …

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The preparation of isotactic polyacrylonitrile using zeolite

The isotactic appears at a lower magnetic field followed by a tactic and syndiotactic signals at lower magnetic fields, respectively. Tacticity was calculated from relative intensities of the respective peaks of nitrile and methine as shown in Table 2. The isotacticity for bulk PAN, calculated on the basis of methine and nitrile, is 26 and 28 ...

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Cryogenic crushing of polystyrene

Atactic and isotactic polystyrene powders were fractured with a ball mill at −196°C. The molecular weight distributions at various milling times measured by GPC show an initial asymmetric broadening and then a gradual returning to the original narrow bell-shaped distribution. Analysis of molecular weight distributions suggests a preferential chain …

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Unusual Tuning of Mechanical Properties of Isotactic …

Preparation, Structure, and Properties of an Isotactic Polypropylene Film with Ultrahigh Content, Ordered, and Continuous β-Transcrystallinity. Macromolecules 2019, 52 (18), 6963-6975.

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Wide and small-angle X-ray scattering study of isotactic polypropylene

Gamma irradiated isotactic polypropylene (IPP) has been studied by means of wide-angle X-ray scattering (WAXS) and small-angle X-ray scattering (SAXS). The skin layer has been investigated by WAXS reflection mode while the core layer underwent WAXS studies by transmission mode. β-IPP has been found solely in the skin layer. An …

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Effect of crystalline transformation on supercritical CO2 …

1. Introduction. Isotactic polybutene-1 (iPB-1) known as "plastic gold", is a polymer renowned for its exceptional properties, including outstanding creep resistance, cracking resistance, and impact resistance [1].These remarkable characteristics make iPB-1 highly sought after in a wide range of applications, such as the pipeline, medical …

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Photooxidative degradation and fragmentation …

The photooxidative degradation and fragmentation behaviors of isotactic polypropylene (itPP) were simulated in laboratory ... sunlight, abrasion by sand/rock, and wave crushing [12].

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Direct azidation of isotactic polypropylene and synthesis of …

Azido-functionalized isotactic polypropylene was prepared via the direct C H azidation of a commercially available polymer using a stable azidoiodinane. Including imidazole or benzimidazole in the reaction mixture was found to significantly improve the yields of the post-polymerization modification.

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Thermal degradation behaviour of isotactic polypropylene …

DOI: 10.1016/J.POLYMDEGRADSTAB.2005.01.052 Corpus ID: 95052790; Thermal degradation behaviour of isotactic polypropylene blended with lignin @article{Canetti2006ThermalDB, title={Thermal degradation behaviour of isotactic polypropylene blended with lignin}, author={Maurizio Canetti and Fabio Bertini and …

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CN1394885A

In the lass lining reflection still that 2000 liters of bands stir, add water purification 1500kg, reach 40-120 purpose isotactic or Atactic Polypropelene 150kg behind the crushing screening, add emulsification promotor 3000g, disperse separant 6000g, activate initiator 3000g, under agitation heat up gradually, when being heated to 90 ℃, be ...

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Isotactic Polymer

Isotactic PP is the well-known semicrystalline material that we all know, while atactic PP is a rubber-like material. The degree of isotacticity determines the "melting point" of the …

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Development of isotactic polypropylene‐based 3D …

The main challenge of fused deposition modeling (FDM) is the limited variety of commercially available semicrystalline polymer materials. Isotactic polypropylene (iPP), with a fast crystallization rate and high crystallinity, tends to undergo extensive volumetric shrinkage during the FDM process, further inducing severe deformation and poor …

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Photooxidative degradation and fragmentation behaviors of …

The photooxidative degradation and fragmentation behaviors of isotactic polypropylene (itPP) were simulated in laboratory after various postconditions, such as quenching, gradual cooling and ...

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Competition of shearing and cavitation effects on the …

Furthermore, in the case of stretching shish-kebab crystal of isotactic polypropylene (iPP), cavitation is activated just after the shearing of crystal at the anchor point of daughter lamellae. According, they concluded that cavitation is directly initiated within the crystalline layers after lamellar shearing. It is still controversial that ...

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Probing into the epitaxial crystallization of β form isotactic

Compared with the most stable crystalline form of isotactic polypropylene (α-iPP), β-iPP shows superior impact strength and high temperature performance, though the mechanism of how the frustrated structure of β-iPP is formed still remains unclear.

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Investigation on structural changes of isotactic polypropylene

Isotactic polypropylene with MFR (melt flow rate) of 3.6 g/10 min at 230 °C/2.16 kg is a product of Sinopec Beijing Yanshan Company. The iPP film with thickness about 80 μm sandwiched between two polytetrafluoroethylene films was heated to 210 °C and held at that temperature for 5 min, and then was quickly immersed into ice water …