Comb-like copolymer dispersant for PP/CaCO3 composites: effects of particle concentration on properties of composites

2017 ◽  
Vol 37 (6) ◽  
pp. 607-616 ◽  
Author(s):  
Xiwei Jing ◽  
Weiguang Gong ◽  
Zhongjun Feng ◽  
Xin Meng ◽  
Baicun Zheng

Abstract A comb-like copolymer poly (styrene-co-maleic anhydride)-graft-poly (ε-caprolacton) (SMA-g-PCL, SP) with carboxyl group as an anchoring group and polycaprolactone as a solvent chain was used as an effective dispersant for CaCO3 in the polypropylene (PP) matrix. The effects of CaCO3 concentration on crystallization behaviors, mechanical properties, and thermal stabilities were studied systematically. The results revealed that the dispersion of CaCO3 in the PP matrix was markedly improved owing to the steric hindrance effect caused by PCL, and the SP-coated CaCO3 was a very effective nucleating agent for PP. Proper CaCO3 concentration corresponded to the improvement of crystallization temperature, crystallinity, and crystallization rate of PP. There was only a slight improvement in yield stress but great improvement in Young’s modulus, flexural modulus, and impact strength. However, the excessive CaCO3 filler deteriorated the mechanical properties. The good dispersion of SP-coated CaCO3 in the PP matrix also accounted for the improvement of thermal stability. The initial decomposition temperature of the PP/CaCO3 composite with 7.4 wt.% CaCO3 increased 35°C compared with neat PP.

2013 ◽  
Vol 833 ◽  
pp. 317-321 ◽  
Author(s):  
Feng Zhan ◽  
Nan Chun Chen ◽  
Xiao Hu Zhang ◽  
Bin Huang ◽  
Zhi Neng Wu ◽  
...  

Mechanical properties, abrasion properties, thermal stabilities, and dynamic mechanical properties of poly (vinyl chloride) (PVC)/diatomite composites with different diatomite content prepared by melting blending were investigated. The results indicated that mechanical properties of composites have different performance due to diatomite participation, and the flexural modulus was improved. With an increase in diatomite, the abrasion resistance and thermal stability of composites were improved. Furthermore, the E' and Tg of composites could be enhanced effectively with diatomite participation. The optimum combined properties of PVC/diatomite composite were obtained with the adding of 40 phr diatomite.


2018 ◽  
Vol 31 (1) ◽  
pp. 43-50 ◽  
Author(s):  
Yingshuang Shang ◽  
Xian Wu ◽  
Yifan Liu ◽  
Zilong Jiang ◽  
Zhaoyang Wang ◽  
...  

The high strength of multiwalled carbon nanotubes (MWCNTs) indicates promising properties for industry applications to reduce frictional coefficient and improve mechanical properties, yet few researches have referred to its structural morphology on the thermal, mechanical, and tribological properties of composites. In this work, three different lengths of MWCNTs were used to prepare polyether ether ketone (PEEK) composites and investigate the effect of structural morphology of MWCNTs on the thermal, mechanical, and tribological properties of composites. Different lengths of MWCNTs endowed PEEK composites with different thermal, mechanical, and tribological properties. On thermal and mechanical properties, the incorporation of 10–30 μm length of MWCNTs increased more the effectiveness on the crystallization rate, showing a higher crystallization temperature and the best mechanical properties of the PEEK composites. On tribological properties, approximately 50 μm MWCNTs can effectively decrease adhesive wear, which is a benefit of forming a thin transfer film, thereby effectively decreasing the coefficient of friction and improving the wear resistance.


2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
C. P. Rejisha ◽  
S. Soundararajan ◽  
N. Sivapatham ◽  
K. Palanivelu

This paper evaluated the effect of multiwall carbon nanotube (MWCNT) on the properties of PBT/PC blends. The nanocomposites were obtained by melt blending MWCNT in the weight percentages 0.15, 0.3, and 0.45 wt% with PBT/PC blends in a high performance corotating twin screw extruder. Samples were characterized by tensile testing, dynamic mechanical analysis, thermal analysis, scanning electron microscopy, and X-ray diffraction. Concentrations of PBT and PC are optimized as 80 : 20 based on mechanical properties. A small amount of MWCNT shows better increase in the thermal and mechanical properties of the blends of PBT/PC nanocomposite when compared to nanoclays or inorganic fillers. The ultimate tensile strength of the nanocomposites increased from 54 MPa to 85 MPa with addition of MWCNT up to 0.3% and then decreased.The tensile modulus values were increased to about 60% and the flexural modulus was more than about 80%. The impact strength was also improved with 20% PC to about 60% and with 0.15% MWCNT to about 50%. The HDT also improved from 127°C to 205°C. It can be seen from XRD result that the crystallinity of PBT is less affected by incorporating MWCNT. The crystallizing temperature was increased and the MWCNT may act as a strong nucleating agent.


2019 ◽  
Vol 27 (1(133)) ◽  
pp. 37-44
Author(s):  
Marcin Barburski ◽  
Mariusz Urbaniak ◽  
Sanjeeb Kumar Samal

In this article, the mechanical properties of biaxial and triaxial woven aramid fabric and respective reinforced composites were investigated. Both fabrics had the same mass/m2. The first part of the experimental investigation was focused on the mechanical properties of different non-laminated aramid fabrics (biaxial and triaxial). The second part was concerned with the mechanical properties of composites made of a different combination of layers of fabric reinforced with an epoxy resin matrix in the order of biaxial+biaxial, trixial+triaxial and biaxial+triaxial. The composites were tested for tensile strength, flexural strength, strain and Young’s and flexural modulus. It can be seen from the results that the density and direction of the yarns are the most important parameters for determination of the strength of the fabric reinforced composite. The biaxial composite clearly showed better tensile strength, while the bi-tri axial order showed good flexural strength compared to the other composite combinations. These fabric reinforced composites have suitable applications in the areas of medical, protection and in the automotive industries.


Polymers ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 389
Author(s):  
Siti Shazra Shazleen ◽  
Tengku Arisyah Tengku Yasim-Anuar ◽  
Nor Azowa Ibrahim ◽  
Mohd Ali Hassan ◽  
Hidayah Ariffin

Polylactic acid (PLA), a potential alternative material for single use plastics, generally portrays a slow crystallization rate during melt-processing. The use of a nanomaterial such as cellulose nanofibers (CNF) may affect the crystallization rate by acting as a nucleating agent. CNF at a certain wt.% has been evidenced as a good reinforcement material for PLA; nevertheless, there is a lack of information on the correlation between the amount of CNF in PLA that promotes its functionality as reinforcement material, and its effect on PLA nucleation for improving the crystallization rate. This work investigated the nucleation effect of PLA incorporated with CNF at different fiber loading (1–6 wt.%) through an isothermal and non-isothermal crystallization kinetics study using differential scanning calorimetry (DSC) analysis. Mechanical properties of the PLA/CNF nanocomposites were also investigated. PLA/CNF3 exhibited the highest crystallization onset temperature and enthalpy among all the PLA/CNF nanocomposites. PLA/CNF3 also had the highest crystallinity of 44.2% with an almost 95% increment compared to neat PLA. The highest crystallization rate of 0.716 min–1 was achieved when PLA/CNF3 was isothermally melt crystallized at 100 °C. The crystallization rate was 65-fold higher as compared to the neat PLA (0.011 min–1). At CNF content higher than 3 wt.%, the crystallization rate decreased, suggesting the occurrence of agglomeration at higher CNF loading as evidenced by the FESEM micrographs. In contrast to the tensile properties, the highest tensile strength and Young’s modulus were recorded by PLA/CNF4 at 76.1 MPa and 3.3 GPa, respectively. These values were, however, not much different compared to PLA/CNF3 (74.1 MPa and 3.3 GPa), suggesting that CNF at 3 wt.% can be used to improve both the crystallization rate and the mechanical properties. Results obtained from this study revealed the dual function of CNF in PLA nanocomposite, namely as nucleating agent and reinforcement material. Being an organic and biodegradable material, CNF has an increased advantage for use in PLA as compared to non-biodegradable material and is foreseen to enhance the potential use of PLA in single use plastics applications.


2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Nguyen Thi Thuy ◽  
Pham Ngoc Lan

To minimize the brittleness of polylactic acid (PLA), the epoxidized rubber seed oils (ERO) or epoxidized ester rubber seed oils (EERO) are blended with PLA. The mechanical properties of ERO bioblend are higher than that of EERO bioblend and significantly improved compared to that of the PLA sample. Elongation at break is increased by 9.1 times, and impact strength and tensile toughness improved by 139% and 1370%, respectively. The morphological study showed the microdroplets of epoxidized oils distributed in the ERO bioblend are much smaller than those in the EERO bioblend. This means that the ERO is better compatible with PLA, and both ERO and EERO are partially miscible with PLA. This compatibility is confirmed by the decrease in the glass transition temperature, T g , from 65.7 to 60.5°C. The TGA analysis shows a sharp increase in an initial decomposition temperature (from 261.8 to 311.9°C) meaning an improvement in thermal properties. The NMR analysis proves that the epoxidized vegetable oils are linked to PLA chains, so both the melt flow index and an acid value of ERO or EERO bioblend decrease while the thermal stability is improved. The NMR peak area of some signals shows that the ERO is more attached to PLA, proving better compatibility of ERO with PLA, resulting in higher mechanical properties of ERO bioblend. The plasticizing effect of plasticizers is not dependent on the oxygen-oxirane content of the epoxidized oil but is strongly influenced by the acid value. Overall results show that both ERO and EERO can be used as a biodegradable, renewable plasticizer to replace petroleum-based plasticizers for PLA. In addition, the successful modification of PLA by using ERO or EERO promotes the use of this polymer as a potential material for researchers working on PLA applications.


2018 ◽  
Vol 31 (4) ◽  
pp. 438-448 ◽  
Author(s):  
Bo Yi ◽  
Yuntao Zhao ◽  
Enling Tian ◽  
Jing Li ◽  
Yiwei Ren

Polyimide (PI) nanofiber membranes were successfully prepared from a PI/N-methyl-2-pyrrolidone (NMP) solution via electrospinning. This technique simply and facilely produced efficient high-performance PI fibers. The morphology, surface wettability, thermal stability, mechanical properties, and filtration performance of the as-prepared PI nanofiber membranes were characterized in detail. The membranes exhibited smooth and hydrophobic surfaces. The nanofibers were well distributed in the membranes with fiber diameters in the range of 140–400 nm. All the PI nanofiber membranes showed excellent thermostability, and their initial decomposition temperature ( Td) and heat resistance temperature ( THRI) exceeded 544.4°C and 198.8°C, respectively. The PI nanofiber membranes also possessed reasonable mechanical properties with a tensile strength and a Young’s modulus reaching 10.5 and 927.6 MPa, respectively. Regarding the filtration performance, the developed nanofiber membranes achieved the best filtration efficiency of 90.4%. Such electrospun PI nanofiber membranes can be a promising candidate for hot gas filtration.


2017 ◽  
Vol 15 (1) ◽  
pp. 248-254 ◽  
Author(s):  
Yan-Hua Cai ◽  
Li-Sha Zhao

AbstractThe introduction of a nucleating agent in semi-crystalline polymers is a frequently utilized way to improve the crystallization performance, and the use of a nucleating agent has a very great effect on the performance of the polymer in other areas including thermal stability and mechanical properties. In this investigation, barium phenylphosphonate (BaP) was prepared as a crystallization accelerator for Poly(L-lactic acid) (PLLA), and the non-isothermal crystallization behavior, thermal stability, and mechanical properties of PLLA modified by BaP were investigated using differential scanning calorimetry (DSC), X-ray diffraction (XRD), thermogravimetric analysis (TGA), and electronic tensile testing. Non-isothermal crystallization analysis showed that the BaP could significantly accelerate the crystallization of PLLA, and the non-isothermal crystallization peak shifted to a higher temperature with increasing concentration of BaP, however, the corresponding crystallization peak became wider. XRD results after non-isothermal crystallization confirmed the non-isothermal crystallization DSC results. Additionally, the addition of BaP did not change the crystal form of PLLA. A comparative study on thermal stability indicated that BaP decreased the onset decomposition temperature of PLLA, resulting from the formation of more tiny and imperfect crystals. Whereas the influence of BaP on the thermal decomposition profile of PLLA was negligible. In terms of mechanical properties, the tensile strength and elastic modulus of PLLA/BaP increased compared to the virgin PLLA, unfortunately, the elongation at break decreased.


2020 ◽  
Vol 57 (3) ◽  
pp. 28-40
Author(s):  
Hao Huang ◽  
Yan-Hua Zhang ◽  
Li-Sha Zhao ◽  
Guang-Ming Luo ◽  
Yan-Hua Cai

This work was aimed at synthesizing the N, N -isophthalic bis(piperonylic acid) dihydrazide (PAID) to be as a new crystallization accelerator for poly(L-lactide) (PLLA), and a detailed investigations of the non-isothermal crystallization, melting behavior, thermal decomposition behavior and mechanical properties of PLLA nucleated by PAID were performed applying differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and electronic tensile tester. The melt-crystallization proved that the PAID could act as a heterogeneous nucleating agent to significantly promote the crystallization in cooling, even the crystallization was still able to be accelerated upon the fast cooling at 50 oC/min. The final melt temperature was another crucial factor for PLLA�s melt crystallization, and when the final melt temperature was 170 oC, the onset crystallization temperature and melt-crystallization enthalpy was almost up to 150 oC and 56.8 J/g upon cooling of 1 oC/min, respectively. Furthermore, the chemical nucleation was proposed to be the nucleation mechanism of PAID for PLLA via the preliminary theoretical calculation. For the cold-crystallization, the addition of PAID exhibited an inhibition for the crystallization of PLLA, but the total crystallization process depended on the heating rate and PAID concentration. The single melting peak after cooling of 1 oC/min indicated that the crystallization had been thoroughly completed in cooling. Additionally, the single melting peak with different locations after full crystallization resulted from the different crystallization temperatures. A comparison in the onset decomposition temperature implied that the presence of PAID only slightly decreased the thermal stability of PLLA. The mechanical testing showed that, in contrast with the elongation at break, the existence of PAID enhanced the tensile strength of PLLA.


2021 ◽  
Author(s):  
Yajun Chen ◽  
Jingxiu He ◽  
Zhe Sun ◽  
Bo Xu ◽  
Juan Li ◽  
...  

Abstract Cellulose nanocrystals (CNCs) have been used as bio-based carbon source in intumescent system. However, CNCs have the disadvantages of low onset decomposition temperature and decompose and carbonize during processing. We, herein, demonstrated the design of phosphazene-containing CNCs (P/N-CNCs) with great thermal stability and outstanding charring ability. The TGA results showed that the initial decomposition temperature of P/N-CNCs was increased from 202.4 ℃ to 272.2 ℃ (increased by 34.5%), and the residual char at 700 ℃ was increased from 24.9 wt% to 55.8 wt% compared with CNCs. Then, flame retardant PLA composites were prepared by blending PLA, P/N-CNCs with ammonium polyphosphate (APP), melamine (MPP), aluminum hypophosphite (AHP) and piperazine pyrophosphate (PPAP), respectively. The thermal stability, flame retardant properties and mechanical properties of PLA composites were investigated. The results showed that the flame retardant system constructed by 7 wt% APP and 3 wt% P/N-CNCs had the best effect in PLA. PLA/7APP/3P/N-CNCs had the highest limit oxygen index value (28.1%), the lowest peak heat release rate (266 kW/m2) and reached UL 94 V-0 rating. Moreover, the tensile strength, impact strength and elongation at break of PLA/7APP/3P/N-CNCs were increased by 7.3%, 18.6% and 29.4%, respectively, compared with these properties of PLA/7APP/ 3CNCs. This work provides a new idea for the design of CNCs with great thermal stability and outstanding charring ability, and offers a new method for the preparation of high-performance flame-retardant PLA composites.


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