Crystallization of glass-fiber-reinforced polyamide 66 composites: Influence of glass-fiber content and cooling rate

J of Applied Polymer Sci

Zhang

et al. 2017

A two-step process for preparing glass fibers (GFs) reinforced b-nucleated PP composites was designed and developed. The complementary approach combined GFs reinforcement and b-nucleating agents regulation using N,N 0 -dicyclohexyl-2,6-napthalenedicarboxamide (TMB-5) in the presence of maleic anhydride grafted polypropylene (PP-g-MA) through extrusion blending. The influence of TMB-5 and GFs on the mechanical properties and crystallization behavior of PP was studied by mechanical test, wide-angle Xray diffraction, differential scanning calorimetry, and scanning electron microscopy. A distinct complementary effect of GFs and bnucleating agent TMB-5 on mechanical properties and crystallization behavior of PP was observed. Results showed that addition of 20 wt % GFs and 0.1 wt % TMB-5 into PP matrix with the two-step process could lead to significant increase to its mechanical properties: specifically 64.8% improvement in tensile strength, 107.1% enhancement in flexural modulus, and 167.7% increasement in notched impact strength compared to that of neat PP. Furthermore, with the combination of TMB-5 and GFs, not only led to promoted interfacial adhesion, but also significantly improved overall comprehensive mechanical properties. The complementary process provided an alternative approach for the development of PP with balanced toughnesss and stiffness.

Section: Resultssupporting

confidence: 58%

Glass fiber reinforced and β‐nucleating agents regulated polypropylene: A complementary approach and a case study

Cui

J of Applied Polymer Sci

Zhang

et al. 2017

“…It may be mentioned that the Avrami equation was theoretically derived for spherulites, discs and rods, representing three‐, two‐, and one‐dimensional forms growth . However, the Avrami indexes n shows more complex crystal growth in the present work, which can only suggests that the nucleation mechanisms and crystal growth modes of all samples do not have obvious difference …”

Section: Resultsmentioning

confidence: 48%

“…The results show that Δ E Xt of every sample, except for P50‐50, increases with the increasing degree of crystallinity below 70% relative crystallinity, which is due to the larger and larger resistance of crystallization of the molten molecular chain with the increasing crystals. A higher Δ E Xt corresponds to the weaker crystallization ability of the polymer . It is observed that Δ E Xt of PA66 is lower than that of PA56, which indicates that a lower energy barrier are need to be overcome in the crystallization of PA66 than that of PA56.…”

Section: Resultsmentioning

confidence: 95%

Crystallization of polyamide 56/polyamide 66 blends: Non‐isothermal crystallization kinetics

Kang

J of Applied Polymer Sci

et al. 2018

The non-isothermal crystallization behaviors of PA56, PA66, and PA56/PA66 blends were studied by differential scanning calorimetry. The Jeziorny and Mo's methods were used to analyze their non-isothermal crystallization kinetics. The results indicated that Mo's method was better to describe the experimental data in this work. The crystallization rate of PA56 was much slower than that of PA66. The crystallization rate of PA56/PA66 blend was speeded up significantly with the increasing PA66 content when the PA66 content was less than 30 wt %. Further increase in the PA66 content only leads to relatively less increase of the crystallization rate in the PA56/PA66 blends. Activation energies have been determined with Friedman method. The activation energy of PA56/PA66 blends is decreased and lower than that of PA56. PA66 may play a role of nucleating agent toward PA56 to make it crystallize more easily in PA56/PA66 blends.

“…Melt blending is a simple and efficient modification to obtain GF‐PA6 composites with good bonding between GF and a PA6 matrix to improve the mechanical properties of composites. Some methods of reducing water absorption for GF‐PA6 have been reported.…”

Section: Introductionmentioning

confidence: 99%

Synergistic effect of polyfunctional silane coupling agent and styrene acrylonitrile copolymer on the water‐resistant and mechanical performances of glass fiber–reinforced polyamide 6

Polymers for Advanced Techs

Yang

et al. 2019

Adverse effects of a high-water absorption rate on properties of a glass fiberreinforced polyamide 6 (GF-PA6) composite significantly reduce performance and limit application in humid environments. In this paper, a polyfunctional silane (PFS) coupling agent with amino (-NH 2 ) and imino (-NH) groups and styrene acrylonitrile copolymer (SAN) were added to a composite, GF-PA6, to prepare GF-PA6/SAN/ PFS composites via melt blending in a twin-screw extruder. The effects of SAN and PFS content on the static and dynamic mechanical properties of the composites before and after water absorption were investigated in detail. The microstructure of the fracture surface was analyzed by a scanning electron microscope (SEM). The results show that the addition of SAN and PFS could effectively inhibit water absorption of the GF-PA6 composites. The alkoxyl groups on PFS reacted chemically with the nitrile groups of SAN, which enriched SAN on the interface between the fiber and matrix during the extrusion and mixing process to improve the effect of water prevention. Therefore, the mechanical properties of the wet state were notably improved while preventing water from permeating the interface by only the addition of a small amount of SAN and PFS. Dynamic mechanical analysis (DMA) results showed that the addition of PFS improved the compatibility of PA6 with SAN and enhanced the interface adhesion between fiber and PA6. In terms of test result of the comprehensive performance, 10 phr SAN with 0.6 phr PFS was the best dosage. KEYWORDS glass fiber (GF), polyamide 6 (PA6), polyfunctional silane (PFS) coupling agent, styrene acrylonitrile copolymer (SAN)