High Β-phase Content Research Articles

PANI/PVDF-TrFE porous aerogel bulk piezoelectric and triboelectric hybrid nanogenerator based on in-situ doping and liquid nitrogen quenching

Limited by the inherent properties of being difficult to be polarized due to its high resistance, PVDF bulk material with high β-phase content is hard to obtain by conventional methods which are suitable for membrane material. Herein, a novel strategy is proposed for the mass production of high-performance β-PVDF-based piezoelectric and triboelectric hybrid nanogenerator (PTNG) employing large-scale PVDF films or bulks by using liquid nitrogen to induce a phase transition and in-situ doped conductive polyaniline (PANI). Polyvinylidene fluoride-trifluoroethylene (PVDF-TrFE) with high piezoelectric coefficient, filled with PANI as a conductive material and sodium carboxymethyl cellulose (SCMC) for increasing porosity, is hot pressed to obtain a composite piezoelectric polymer for PTNG. The subsequent “quenching” process of the piezoelectric polymer allows its high content of β-phase, which in turn makes the PTNG exhibit excellent piezoelectric properties. The optimal output of the PTNG, with a β-phase content of up to 71%, reaches 246 V and 122 μA at the frequency of 30 Hz and pressure of 0.31 MPa, and the power density is calculated to be 6.69 W/m 2 . Moreover, the PTNG can directly light up 119 blue light-emitting diodes (LEDs) with a size of 3 mm in series. The excellent performance verifies the reliability and accuracy of the method, that is, the β-phase transformation of disordered amorphous PVDF occurs at low temperature and high-rate quenching, and PANI opens the channel for carriers to move charge in the bulk material. This innovative method presented here is a simple and efficient approach for preparation of bulks with high β-phase and low internal resistance, which undoubtedly provides a feasible direction for the industrialization of high-performance PENGs. A novel PANI/PVDF-TrFE porous aerogel bulk piezoelectric/triboelectric nanogenerator (PTNG) is prepared based on in-situ doping and liquid nitrogen quenching. The rapidly fabricated PTNG exhibits satisfactory performance (U = 246 V, I = 122 μA, Q = 6.69 W/m 2 ) and can light up 119 blue light-emitting diodes in series with a size of 3 mm. The PVDF-based piezoelectric bulk eliminating the need of polarization treatment exhibits excellent electrical properties and will undoubtedly show encouraging potential in the industrialization of high-performance PTNG devices. • High-rate quenching of liquid nitrogen achieves β-phase transformation of the bulk. • Polyaniline can enhance the charge transfer efficiency and improve the output performance of bulk nanogenerators. • The decomposition of SCMC realizes the preparation of thermoformed porous bulk, thereby improving the output performance of PTNG. • The prepared PANI/PVDF-TrFE PTNG exhibits excellent performance (U = 246 V, I = 122 μA, Q = 6.67 W/m 2 ). • The PTNG can directly illuminate 119 blue light-emitting diodes (LEDs) with a size of 3 mm in series.

Mechanism of a Self-Assembling Smart and Electrically Responsive PVDF-Graphene Membrane for Controlled Gas Separation.

The development of science and technology is accompanied by a complex composition of multiple pollutants. Conventional passive separation processes are not sufficient for current industrial applications. The advent of active or responsive separation methods has become highly essential for future applications. In this work, we demonstrate the preparation of a smart electrically responsive membrane, a poly(vinylidene difluoride) (PVDF)-graphene composite membrane. The high graphene content induces the self-assembly of PVDF with a high β-phase content, which displays a unique self-piezoelectric property. Additionally, the membrane exhibits excellent electrical conductivity and unique capacitive properties, and the resultant nanochannels in the membrane can be reversibly adjusted by external voltage applications, resulting in the tailored gas selectivity of a single membrane. After the application of voltage to the membrane, the permeability and selectivity toward carbon dioxide increase simultaneously. Moreover, atomic-level positron annihilation spectroscopic studies reveal the piezoelectric effect on the free volume of the membrane, which helps us to formulate a gas permeation mechanism for the electrically responsive membrane. Overall, the novel active membrane separation process proposed in this work opens new avenues for the development of a new generation of responsive membranes.

Design of an Ultrasensitive Flexible Bend Sensor Using a Silver-Doped Oriented Poly(vinylidene fluoride) Nanofiber Web for Respiratory Monitoring.

We propose a design strategy to fabricate a flexible bend sensor (BS) with ultrasensitivity toward airflow using all-poly(vinylidene fluoride) (PVDF) nanofiber web-based sensing elements and electrodes to monitor human respiration. The unique electrospinning (rotational speed of collector of 2000 rpm and tip-to-collector distance of 4 cm) with silver nanoparticle interfacing was introduced to prepare a Ag-doped oriented PVDF nanofiber web with high β-phase content as a sensing element (AgOriPVDF, β-phase crystallinity ∼44.5%). After that, a portion of the prepared AgOriPVDF was processed into a flexible and electrically conductive electrode through an electroless silver plating technique (SP-AgOriPVDF). Interestingly, the encapsulated AgOriPVDF BS with the SP-AgOriPVDF electrode exhibited superior piezoelectric bending response (open-circuit peak-to-peak output voltage, Vp-p ≈ 4.6 V) to injected airflow, which is more than 200 times higher than that of the unpackaged randomly aligned PVDF nanofiber web BS with a conductive tape electrode (Vp-p ≈ 0.02 V). In addition, the factors influencing the bend sensitivity of the BS such as the β-phase content, nanofiber orientation, flexibility of the electrode, and so forth were thoroughly analyzed and then discussed. We also demonstrated that the AgOriPVDF BS has sufficient capability to detect and identify various respiratory signals, presenting a great potential for wearable applications, for example, smart respiratory protective equipment.

Preparation of PVDF flexible piezoelectric film with high β-phase content by matching solvent dipole moment and crystallization temperature

In Poly(vinylidene fluoride) (PVDF) polymer films, α-phase usually dominates and leads to weak electrical properties, limiting its applications in microelectronics. In this paper, the effects of dipole moment of the solvent and the crystallization temperature on β-phase content in PVDF films have been systematically investigated. Variations in crystalline phases were confirmed by using X-ray diffractometer (XRD), Fourier transform infrared spectra (FTIR) and differential scanning calorimetry (DSC). The results verified that larger dipole moment of the solvent is more beneficial to the formation of β-phase in PVDF films. PVDF films with high content of β-phase up to 98.8% are obtained by using dimethylsulfoxide (DMSO) as the solvent at optimized crystallizing temperature of 60 °C. The corresponding PVDF film with high β-phase content presents excellent ferroelectric and piezoelectric properties, with a remnant polarization (Pr) and piezoelectric coefficient (d33) of 7.7 μC/cm2 and − 25.8 pC/N, respectively. It is worth mentioning that this high d33 compares that of the expensive PVDF-based copolymers and complexes. The process displayed in this research provided a feasible method to the preparation of low cost PVDF films for flexible piezoelectric sensors and actuators.

Immobilized ionic liquid induced electroactive β-phase in poly(vinylidene fluoride) thin films

Ferroelectric poly(vinylidene fluoride) (PVDF) has been proposed in the past decades as an electroactive material for various applications in microelectronic devices due to its ferro/piezo/pyroelectric properties. However, fabrication of smooth PVDF thin films with a high content of β-phase and controlled chain orientation is a long-standing problem. Here we report on the control over polymorphs of PVDF thin films by exploring the interfacial ion-dipolar interactions. The ion-dipolar interactions are provided by CF2 bonds of PVDF and imidazolium type ionic liquid immobilized onto substrates via biomimetic catecholic attachment chemistry. By simply melt crystallization of spin-coated PVDF thin films at elevated temperatures, the ferroelectric polar β-phase with a lying-down chain orientation is formed. The thin films exhibit excellent ferro/piezoelectric properties when applying electric field due to the immobilization of ionic liquids. The results may boost the applications of PVDF in microelectronic devices.

3D printing of electroactive PVDF thin films with high β-phase content

Bi-axially oriented electroactive PVDF thin films were prepared by a 3D printing process during which multiple parameters play a critical role in enhancing β-phase and crystallinity of the thin films. The PVDF molecular chains were rotated and stretched to form orderly arrangement by the pulling of in situ strong auxiliary electric potential (voltage) and the mechanical pulling force, and the aligned PVDF molecular chains improved the crystallinity of the thin films. Doping very small amount of multi-walled carbon nanotubes (MWCNTs) or graphene (GR) as a nucleating agent significantly increased the content of the β-phase in the films. Adding GR behaved is better than the MWCNTs in improving the β-phase due to the lamellar structure of graphene can generate a large number of micro electric fields stimulating the transformation of molecular chain from trans-gauche-trans-gauche(TG+TG−) to all-trans (TTTT). The content of β-phase in the PVDF/GR(0.03 wt%) composite thin film researched at 61.52%. Under the special environment of 3D printing, the printed PVDF thin films became very dense with high β-phase after depositing layer-by-layer. It exhibited good piezoelectric properties without post-poling treatment and mechanical stretching.

Effects of temperature on the β-phase depletion in MCrAlYs: A modelling and experimental study towards designing new bond coat alloys

This paper investigates the effects of varied temperature conditions on the kinetics of β-phase depletion in MCrAlYs by DICTRA diffusion simulations and experimental observations. A commercially available MCrAlY composition and two modelled compositions were examined at temperature regimes of 1000 °C, 1100 °C and 1200 °C. A previously developed temperature-dependent oxidation model was used at the boundary to examine the β-phase depletion kinetics at different temperatures. The oxide growth kinetics and the corresponding Al flux were calculated based on the oxidation model. The MCrAlY phase equilibrium calculations were conducted in Thermo-Calc and the oxidation-diffusion simulations were carried out using the finite difference diffusion software, DICTRA. It was found that the MCrAlYs exhibit a predominantly dual-phase γ + β structure at 1000 °C and above. It was revealed that varying the temperature had a strong effect on the β-phase depletion in low Al-content MCrAlYs from DICTRA simulations and available experimental measurements. In addition, it was demonstrated from the diffusion simulations that MCrAlYs with high Al content exhibit an enhanced lifetime in maintaining the two-phase structure with less β-phase depletion at high temperatures due to the high Al and β-phase content.

Enhanced piezoelectric output of the PVDF-TrFE/ZnO flexible piezoelectric nanogenerator by surface modification

In this paper, ZnO nano-particles (NPs) were modified by adding a dispersant (n-propylamine, PA) and a silane coupling agent (1H, 2H, 1H, 2H, Perfluorooctyltriethylsilane, PFOES) simultaneously. Further, the PVDF-TrFE/modified ZnO composite films with high crystallinity and large specific surface area were prepared, which acted as the active layer of the piezoelectric nanogenerator (PENG). Four species of films, pure PVDF-TrFE, PVDF-TrFE/ZnO, PVDF-TrFE/ZnO@PA and PVDF-TrFE/ZnO@PA@PFOES were marked P-0-0-0, P-Z-0-0, P-Z-P-0 and P-Z-P-P, respectively. The crystalline phases of the films were determined by Fourier infrared spectroscopy (FT-IR) and wide-angle X-ray diffraction (WXRD). Scanning electron microscope (SEM), Laser scanning confocal microscope (LSCM), Atomic force microscope (AFM) and water contact angle (WCA) measurements were employed to analyze the surface morphology of the films. The thermal properties of the materials were characterized with a differential scanning calorimeter (DSC). From the FTIR spectra and WXRD pattern, it was notable that the modified ZnO NPs promoted the crystallization of β-phase. The results showed that the crystallinity of P-Z-P-P was increased by 36.12% compared to P-0-0-0. Combined with the results of SEM, LSCM and AFM, it can be concluded from WCA that modified ZnO NPs can increase the specific surface area of the film. The piezoelectric strain constant d33 value of P-Z-P-P film was 73.5% higher than that of P-0-0-0 film, and the output voltage value of ITO/P-Z-P-P/Au PENG increased 24.4% than that of ITO/P-0-0-0/Au PENG. After 1000 cycles of testing, the output voltage of the ITO/P-Z-P-P/Au PENG has been maintained at 2.40 V, indicating that the generator exhibited the high mechanical endurance. By clarifying the mechanism of surface modification, it can be concluded that enhanced piezoelectric output of the PENG is contributed to both higher β-phase content and larger charge collecting area by surface modification.

Structural and electrical properties of ferroelectric poly(vinylidene fluoride) and mechanically activated ZnO nanoparticle composite films

The influence of the mechanical activation of ZnO nanoparticle fillers on the structural and electrical properties of the matrix of poly(vinylidenefluoride)–ZnO (PVDF–ZnO) films was investigated. Transmission electron microscopy and scanning electron microscopy analyses showed that mechanical activation in a high energy planetary ball mill reduces the size of ZnO particles. X-ray diffraction and Raman spectroscopy revealed that PVDF crystallized predominantly as the γ-phase. Non-activated ZnO filler reduces the degree of the crystallinity of the matrix and promotes crystallization of α-phase of PVDF in the film, while the fillers activated for 5 and 10 min induce crystallization of β-phase, indicating that mechanical activation of the filler can be used as a general method for fabrication of PVDF composites with increased content of piezoelectric β-phase crystals. Dielectric spectroscopy measurements show that polymer composite with the high content of β-phase (with ZnO filler activated for 5 min) exhibits the highest value of dielectric permittivity in 150–400 K range of temperatures. Kinetic analysis shows combined effects of increased surface area and increased concentration of surface defects on the interactions between polymer chains and activated nanoparticles.

Preparation and crystallization of isotactic polypropylene composites filled by titanium dioxide-supported montmorillonite with a β-nucleating surface

To obtain multi-functional β-iPP composites, β-iPP composites are always filled by multiple fillers with α-nucleating ability. To prepare β-iPP/TiO2/MMT composites, TiO2-supported MMT with a β-nucleating surface was prepared through hydrolysis reaction of Tetra-n-butyl titanate and chemical reaction between pimelic acid and calcium ion. X-ray diffraction and scanning electron micrograph confirmed the formation of TiO2 on the surface of MMT. The differential scanning calorimeter and X-ray diffraction illustrated that the β-iPP composites filled by TiO2 and MMT had lower relative β-phase contents than β-iPP. It is observed by polarized optical microscope that addition of TiO2-supported MMT with a β-nucleating surface into iPP can increase the spherulite nuclei density and decrease the spherulite size significantly and obtain the β-iPP/TiO2/MMT composites with high relative β-phase content.

The preparation of calcium pimelate modified OMMT from natural Ca-montmorillonite and its application as β-nucleating agent for polypropylene

Ca-montmorillonite (Ca-MMT) was first modified with different amount of two different kinds of surfactants to obtain organo-montmorillonites (OMMTs) directly via ion exchange between Ca2+ and alkyl ammonium cations. Then remained Ca2+ in OMMTs was reacted with pimelic acid (HA) to obtain CaHA-OMMTs. PP/CaHA-OMMT composites were prepared. Results of FT-IR demonstrate the existence of long-chain alkyl in OMMTs, and CaHA in CaHA-OMMTs. The reaction between HA and OMMT could lead to an increase in d-spacing value of clay. CaHA-OMMTs with high CaHA contents and obviously increased d-spacing values were obtained. Results of WAXD and TEM show exfoliated clay platelets in PP/CaHA-OMMT composites. The obviously increased Tc, and the high β-phase content in PP/CaHA-OMMT composites demonstrate the high β-nucleation efficiency of CaHA-OMMTs. Composites with higher content of β-phase epitaxial crystallized on exfoliated clay platelets display largely improved impact strength.

Enhanced piezoresponse of highly aligned electrospun poly(vinylidene fluoride) nanofibers

Well-ordered nanostructure arrays with controlled densities can potentially improve material properties; however, their fabrication typically involves the use of complicated processing techniques. In this work, we demonstrate a uniaxial alignment procedure for fabricating poly(vinylidene fluoride) (PVDF) electrospun nanofibers (NFs) by introducing collectors with additional steps. The mechanism of the observed NF alignment, which occurs due to the concentration of lateral electric field lines around collector steps, has been elucidated via finite-difference time-domain simulations. The membranes composed of well-aligned PVDF NFs are characterized by a higher content of the PVDF β-phase, as compared to those manufactured from randomly orientated fibers. The piezoelectric energy harvester, which was fabricated by transferring well-aligned PVDF NFs onto flexible substrates with Ag electrodes attached to both sides, exhibited a 2-fold increase in the output voltage and a 3-fold increase in the output current as compared to the corresponding values obtained for the device manufactured from randomly oriented NFs. The enhanced piezoresponse observed for the aligned PVDF NFs is due to their higher β-phase content, denser structure, smaller effective radius of curvature during bending, greater applied strain, and higher fraction of contributing NFs.

Investigation on the crystallization behavior and morphology of β-nucleated isotactic polypropylene/glass fiber composites

ABSTRACTThe isotactic polypropylene (iPP) with different uniformities of stereo-defect distribution was synthesized, and the β-nucleated iPP/glass fiber composites (TPPA-GF and TPPB-GF) were prepared. The influence of glass fiber on the non-isothermal crystallization kinetics, β-phase crystallization, and morphology behavior of the composites were investigated by means of differential scanning calorimetry (DSC), scanning electronic microscopy (SEM), and wide angle X-ray diffraction (WAXD). The results revealed that for both TPPA-GF and TPPB-GF, as the amount of GF increases, the crystallization peak temperature and relative degree of crystallinity increase gradually, while crystallization peak width decreases gradually. Meanwhile, the half crystallization time t1/2 of both TPPA and TPPB decreases gradually, indicating that the addition of GF can accelerate the crystallization of both TPP-A and TPP-B. Moreover, the addition of glass fiber decreases the energy barriers ΔE and makes the composites to crystallize easier. The results of melting behavior study and WAXD indicate that high cooling rate leads to relatively low crystallization temperature and low thermal stability, resulting in higher β-phase content with relatively low thermal stability, while low cooling rate leads to high crystallization temperature and high thermal stability, which is more favorable for the formation of less amount of β-phase with high thermal stability. For both TPPA and TPPB, the higher the content of glass fiber, the lower the βc. The addition of glass fiber not only reduces the content of β-phase but also destroys its spherulite morphology. It was also observed that the glass fiber is more uniformly dispersed in TPPB compared with TPPA.

Facile preparation of highly oriented poly(vinylidene fluoride) uniform films and their ferro- and piezoelectric properties

The shear-induced PVDF films present preferentially orientation with a high β-phase content and exhibit excellent ferro- and piezoelectric properties.

Effects of in-situ poling and process parameters on fused filament fabrication printed PVDF sheet mechanical and electrical properties

Polyvinylidene fluoride (PVDF) is a polymer prized for its unique material properties, including a high resistance to corrosive acids such as HCL and HF and its piezoelectric potential based on the proper microstructure arrangement. In this work, the effects of fused filament fabrication (FFF) routine parameters on printed PVDF film properties were investigated using a variety of experimental methods. The influence of in-fill angle (0°, 45°, and 90°) on the effective Young’s Modulus, Poisson’s ratio, and yield strength were evaluated using tensile testing and a digital image correlation (DIC) analysis. The phase content, in particular the β-phase amount, within the semi-crystalline PVDF films was determined as a function of processing parameters using the FTIR method. Considered parameters included the extrusion temperature, horizontal speed, in-situ applied hot end voltage, and bed material. Results showed that higher β-phase content was associated with lower extrusion temperatures, faster extrusion rates, and higher hot end voltages. While all “as printed” films demonstrated little to no measurable piezoelectricity, PVDF films printed with a high β-phase content and subjected to a post-printing corona poling procedure showed a small, but consistent piezoelectric response. Based on a static deflection cantilever beam experiment, the d31 coefficient of the poled specimens was estimated at 1.19 pm/V.

Synergistic toughening effect of β-nucleating agent and long chain branching on polypropylene random copolymer

β-nucleated long chain branched (LCB) polypropylene random copolymers (PPRs) were prepared via reactive extrusion by introducing β nucleating agent (NA), dicumyl peroxide (DCP) and various contents of 1, 6-Hexanediol diacrylate (HDDA) into PPR. Results of Fourier infrared spectroscopy (FTIR) and the rheological properties demonstrate the existence of LCB polypropylene. Mechanical properties including impact strength, tensile strength and elongation at break were studied. The crystal structure, morphology and crystallization behavior were investigated via wide-angle X-ray diffraction (WAXD), polarized light microscopy (PLM) and differential scanning calorimetry (DSC). Non-isothermal crystallization kinetics using the Jeziorny method was also studied. The results show an increased LCB degree with increasing HDDA amount. For the sample with a moderate LCB level, synergistic toughening effect of NA and LCB is achieved without deterioration of yield strength or elongation at break, partially because of its higher β-phase content and much smaller spherulite size. It exhibits the minimum values of Tc and Zc1, and the maximum values of t1/2 and n1 in the primary stage of crystallization, regardless of the cooling rate, indicating a slower crystallization rate and more complicated nucleation and crystal growth model.

High β phase content in PVDF/CoFe2O4 nanocomposites induced by DC magnetic fields

Flexible ferroelectrics being exploited as energy harvesting and conversion materials are highly desirable for wearable and skin-mountable electronic devices. As one of the most typical ferroelectric polymers, poly(vinylidene fluoride) (PVDF) has been widely used in modern electronic systems and devices, whose ferroelectric performance relies heavily on its β phase content. In this work, to achieve high-β-phase-content PVDF, we first introduced CoFe2O4 nanoparticles into PVDF. With the incorporation of CoFe2O4 nanoparticles used as an effective polymer nucleation agent, the percentage of the β phase in the PVDF has been significantly enhanced, e.g., 84% in the nanocomposite with 5 wt. % CoFe2O4 versus only 73% in the pure PVDF. In order to further increase the β phase content in PVDF, we subsequently proposed an easily realized strategy. By applying DC magnetic fields during the solution-casting process of the PVDF/CoFe2O4 nanocomposites, a further improved β phase content as high as 95% can be achieved. The further improvement of the β phase content is attributable to the tensile stress at the CoFe2O4/PVDF interfaces created by the coupling of magnetic field and CoFe2O4 by means of the magnetostriction effect. The high β-phase content makes the PVDF/CoFe2O4 nanocomposites a promising candidate for flexible and wearable electronic device applications.

Enhanced β Crystalline Phase in Poly(vinylidene fluoride) via the Incorporation of Graphene Oxide Sheets assisted by Supercritical CO2 Treatment

ABSTRACTGraphene oxide (GO) sheets were pre-modified with a typical piezoelectric polymer, poly(vinylidene fluoride) (PVDF), using a simple supercritical carbon dioxide (SC CO2) method, and then the PVDF-decorated GO was added into a PVDF matrix by solution blending. Transmission electron microscopy (TEM) revealed that the decorating degree of PVDF on the surface of the GO increased significantly with increasing of SC CO2 pressure and PVDF concentration. The mechanism of the polymer adsorption on the GO sheets through favorable interaction between the GO and PVDF chains was identified via Fourier transform infrared spectroscopy (FTIR). Further, the crystallization behavior of PVDF/GO composites was investigated by differential scanning calorimetry (DSC), FTIR and polarized optical microscopy (POM). Interestingly, the composite with PVDF-decorated GO as the filler showed higher β-phase content compared to the composite with pristine GO as the filler. The study showed that the supercritical fluid-induced epitaxial crystallization process has significant potential for fabricating functional GO-based nanocomposties containing piezoelectric or conducting materials.

A novel montmorillonite with β-nucleating surface for enhancing β-crystallization of isotactic polypropylene

Montmorillonite (MMT) generally has α-nucleating ability for isotactic polypropylene (iPP). A novel MMT with β-nucleating surface (β-MMT) supported by chemically calcium pimelate (CaA) was prepared through the chemical reaction between pimelic acid (HA) and calcium ion on the surface of MMT in the first time. Infrared spectrometry and thermogravimetric analysis confirmed the formation of CaA on the surface of MMT. The differential scanning calorimeter and X-ray diffraction illustrated that the iPP nanocomposites filled by MMT and β-MMT exhibit different heterogeneous nucleation. The heterogeneous nucleation of the prepared MMT surface has changed from α-nucleation into β-nucleation and a novel MMT with β-nucleating surface is obtained. Even, the heterogeneous β-nucleating ability of β-MMT is much stronger than that of CaA. Addition of MMT with β-nucleating surface into iPP matrix significantly increased the spherulite nuclei density and decreased the spherulite size, and can easily prepare the β-iPP nanocomposites with high relative β-phase content.

The β-nucleating effect of wollastonite-filled isotactic polypropylene composites

Wollastonite (W) with β-nucleating effect (β-W100) for iPP crystallization was obtained through reaction between Ca2+ in wollastonite and pimelic acid (PA) and the β-iPP composites filled by different content of β-W100 were prepared. The effect of PA and wollastonite contents on β-nucleation, crystallization and melting behavior, and crystalline morphology of W and β-W100-filled iPP composites was investigated by differential scanning calorimetry (DSC), wide-angle X-ray diffraction, and polarizing optical microscopy. The results indicated that incorporation of W and β-W100 increase the crystallization peak temperature of iPP due to its heterogeneous nucleating ability. And iPP/W composites predominantly crystallize in the α-phase iPP and iPP/β-W100 composites in the β-phase iPP. The results of DSC multi-scanning in same and different melting temperatures showed that β-W100 not only has strong heterogeneous β-nucleating effect but also DSC multi-scanning in same and different melting temperatures has no influence on the heterogeneous β-nucleating effect of β-W100. The β-iPP containing high wollastonite content with high β-phase content can be easily prepared.