scholarly journals Mechanically Robust and Flame-Retardant Polylactide Composites Based on In Situ Formation of Crosslinked Network Structure by DCP and TAIC

Polymers ◽  
2022 ◽  
Vol 14 (2) ◽  
pp. 308
Author(s):  
Yajun Chen ◽  
Xingde Wu ◽  
Mengqi Li ◽  
Lijun Qian ◽  
Hongfu Zhou

The addition of intumescent flame retardant to PLA can greatly improve the flame retardancy of the material and inhibit the dripping, but the major drawback is the adverse impact of the mechanical properties of the material. In this study, we found that the flame retardant and mechanical properties of the materials can be improved simultaneously by constructing a cross-linked structure. Firstly, a cross-linking flame-retardant PLA structure was designed by adding 0.9 wt% DCP and 0.3 wt% TAIC. After that, different characterization methods including torque, melt flow rate, molecular weight and gel content were used to clarify the formation of crosslinking structures. Results showed that the torque of 0.9DCP/0.3TAIC/FRPLA increased by 307% and the melt flow rate decreased by 77.8%. The gel content of 0.9DCP/0.3TAIC/FRPLA was 30.8%, indicating the formation of cross-linked structures. Then, the mechanical properties and flame retardant performance were studied. Results showed that, compared with FRPLA, the tensile strength, elongation at break and impact strength of 0.9DCP/0.3TAIC/FRPLA increased by 34.8%, 82.6% and 42.9%, respectively. The flame retardancy test results showed that 0.9DCP/0.3TAIC/FRPLA had a very high LOI (the limiting oxygen index) value of 39.2% and passed the UL94 V-0 level without dripping. Finally, the crosslinking reaction mechanism, flame retardant mechanism and the reasons for the improvement of mechanical properties were studied and described.

Author(s):  
E. Rajamäki ◽  
M. Leino ◽  
P. Vuoristo ◽  
P. Järvelä ◽  
T. Mäntylä

Abstract Three different types of polyethylene powders were flame sprayed onto pre-heated steel substrate previously coated by electrostatic spray system with a thin epoxy primer layer. Properties of the polyethylene (PE) powders, including powder density, particle size and melt flow rate (MFR) were measured in order to study their influence on the mechanical properties of the coating. The spray experiments started with optimization of spraying parameters. The main variables were pre-heating temperature of the substrate, temperature increase during spraying (influenced by the spraying distance), and thickness of the PE coatings. The laboratory tests performed for the coatings were coating characterization by microscopy and mechanical testing. Porosity and thickness of the coatings were determined by optical and stereo microscopy studies from polished cross-sectional samples. Hardness, impact strength, peel strength, and adhesive strength of the coatings were also investigated. Also some hot water sinking and heat cycling tests were performed. As a result from the present studies it can be concluded that powder properties have great influence on the mechanical properties of the final coating.


e-Polymers ◽  
2007 ◽  
Vol 7 (1) ◽  
Author(s):  
Liu Xijun ◽  
Jiang Zhaohua ◽  
Zhu Wenming

AbstractTwo different types of polyolefine (PO) grafted with itaconic acid as a reactive compatibilizer, polypropylene (PP) grafted with itaconic acid (PP-g-ITA) and high density polyethylene (HDPE) grafted with itaconic acid (HDPE-g-ITA), PP and HDPE grafted with copolymer of itaconic acid and styrene (PP-g-(ITA-St) and HDPE-g-(ITA-St)) were prepared by melt graft technique through reactive type twin-screw extruder. FT-IR and thermal analysis were used to characterize the structure of the graft copolymer. The graft ratio (GR) and melt flow rate (MFR) were determined by non-aqueous titration and melt flow rate analyzer. The effect of the concentration of monomer and initiator dosage on GR and MFR of graft copolymer were studied. Then polyamide 6 (PA 6) blends, PA 6/PP (PA 6/HDPE), that compatibilized with PP-g-ITA (HDPE-g-ITA) were prepared. The morphology of the blends was analyzed by SEM, DSC and Molau tests and the mechanical properties of which were characterized by tensile, impact, and bend tests. The results of mechanical property showed that the impact strength of blends was increased by 50% and 70% after PP-g-ITA and HDPE-g-ITA was used as compatibilizer, but the MFR of blends was decreased. The SEM photographs indicated that the accession of compatibilizer obviously improved binding state between two phases in blends, the size of dispersed phase was reduced evidently and the interface became indistinct. DSC results demonstrated that in the case of PP-g-ITA, glass temperature (Tg) of PA 6 matrix in blends was ascended, melt point (Tm) was improved a little, crystallinity (Xc) was decreased, Tm and Xc of PP phase was increased; With the accession of HDPE-g-ITA, Tm of PA 6 matrix and HDPE phase had almost no change, Xc of PA 6 matrix was decreased and Xc of HDPE phase was increased.


2011 ◽  
Vol 284-286 ◽  
pp. 1750-1755
Author(s):  
Jin Zhou Chen ◽  
Zhen Gao ◽  
Peng Ping Xie ◽  
Kai Guo ◽  
Ming Jun Niu ◽  
...  

In order to reduce the cost of the polylactic acid (PLLA) material and to improve its flexibility to expand the application of PLA-based plastic, a series of PLLA/SA blends with tetrabutyl titanate (Ti(OBu)4) used as compatibilizer were prepared in the presence of 10% triethyl citrate (TEC) as plasticizer. It was investigated the effect of the compatibilizer and its content on the mechanical properties, structure and morphologies, heat-resistant performance, melt flow rate, and water-resistant performance and other implications of blends. The results showed that: adding the compatibilizer Ti(OBu)4 could significantly improve the compatibility of PLLA and SA, the mechanical properties and thermal stability of the blends were increased, while melt flow rate and water absorption were decreased. When the content of compatibilizer Ti(OBu)4 was 8 wt%, PLA/SA blends(75/25 wt%) had the best overall performance.


2014 ◽  
Vol 488-489 ◽  
pp. 293-296
Author(s):  
Dong Ze Li ◽  
Xiao Chuan Jia ◽  
Xiu Ping Lu ◽  
Sheng Jia Zhai

A series of polylactic acid (PLA)/IFR composites was prepared by melt blending method.Capillary rheometer and rotary rheometer were applied to investigate the effects of and flame retardants on rheological properties. The results of the rheological test show that the melt flow rate increases with the increasing of content of Intumescent flame retardant. Intumescent flame retardant joined making PLA system flow rate is larger than pure PLA, melt flow rate increases, apparent viscosity decreases, relaxation time decreases, and the complex viscosity decreases gradually with the increase of scanning frequency.


2003 ◽  
Vol 254-256 ◽  
pp. 569-572 ◽  
Author(s):  
Hiroaki Takadama ◽  
Masami Hashimoto ◽  
Yorinobu Takigawa ◽  
Mineo Mizuno ◽  
Tadashi Kokubo

Coatings ◽  
2019 ◽  
Vol 9 (7) ◽  
pp. 457 ◽  
Author(s):  
Sven Sängerlaub ◽  
Marleen Brüggemann ◽  
Norbert Rodler ◽  
Verena Jost ◽  
Klaus Dieter Bauer

Taking into account the current trend for environmentally friendly solutions, paper coated with a biopolymer presents an interesting field for future packaging applications. This study covers the application of the biopolymer poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) on a paper substrate via extrusion coating. The intention of this study is to analyse the effect of a plasticiser on the processability (melting point, film thickness) and the final properties (crystallinity, elongation at break) of PHBV. Up to 15 wt.% of the plasticisers triethyl citrate (TEC) and polyethylene glycol (PEG) were used as additive. The processing (including melt flow rate) as well as the structural properties (melting and crystallisation temperature, surface structure by atomic force microscopy (AFM), polarisation microscopy, scanning electron microscopy (SEM)), mechanical properties (elongation at break, tensile strength, elastic modulus, adhesion), and barrier properties (grease) of these blends and their coating behaviour (thickness on paper), were tested at different extrusion temperatures. The melting temperature (Tm) of PHBV was reduced by the plasticisers (from 172 °C to 164 resp. 169 °C with 15 wt.% TEC resp. PEG). The minimal achieved PHBV film thickness on paper was 30 µm owing to its low melt strength. The elastic modulus decreased with both plasticisers (from 3000 N/mm2 to 1200 resp. 1600 N/mm2 with 15 wt.% TEC resp. PEG). At 15 wt.% TEC, the elongation at break increased to 2.4 length-% (pure PHBV films had 0.9 length-%). The grease barrier (staining) was low owing to cracks in the PHBV layers. The extrusion temperature correlated with the grease barrier, mechanical properties, and bond strength. The bond strength was higher for films extruded with a temperature profile for constant melt flow rate at different plasticiser concentrations. The bond strength was max. 1.2 N/15 mm. Grease staining occurs because of cracks induced by the low elongation at break and high brittleness. Extrusion coating of the used specific PHBV on paper is possible. In further studies, the minimum possible PHBV film thickness needs to be reduced to be cost-effective. The flexibility needs to be increased to avoid cracks, which cause migration and staining.


2019 ◽  
Vol 814 ◽  
pp. 256-261
Author(s):  
Jun Wen ◽  
Qiong Zhang ◽  
Zhi Feng Zhu ◽  
Feng Wang

Acrylonitrile-butadiene-styrene (ABS) was modified by aluminum oxide (AL2O3), talcum powder, kaolin and CaCO3. ABS samples were printed by 3D printer after the ABS silk was made. Then the mechanical properties, morphology, melt flow rate were studied in this article. AL2O3 has the best enhancement effect on ABS than other particles, and the melt flow rate was improved when content of AL2O3 less than 10%.


2013 ◽  
Vol 750-752 ◽  
pp. 85-89
Author(s):  
Xing Luo ◽  
Min He ◽  
Jian Bing Guo ◽  
Bin Wu

The effects of brominated flame retardant which composed of decabromodiphenyl ethane (DBDPE) and antimonous oxide (AO) on long glass fiber reinforced polypropylene (LGFPP) were investigated by means of limiting oxygen index (LOI), vertical burning (UL-94), thermogravimetry analysis (TGA), and mechanical properties. With the increase of DBDPE-AO content, the LOI values of DBDPE-AO/LGFPP composites increased from 21 to 27.6, and when the content of DBDPE-AO was 16wt%, the composites passed the V-0 rating in UL-94 testing. The experimental results showed that the brominated flame retardant improved flame retardancy of LGFPP, which was proved by the TGA testing. Whats more, the mechanical properties of composites even improved compared with pure LGFPP.


RSC Advances ◽  
2015 ◽  
Vol 5 (21) ◽  
pp. 16328-16339 ◽  
Author(s):  
Rui-Min Li ◽  
Cong Deng ◽  
Cheng-Liang Deng ◽  
Liang-Ping Dong ◽  
Hong-Wei Di ◽  
...  

The water resistance, flame retardancy and mechanical properties of POE intumescent flame-retardant systems were improved simultaneously.


2011 ◽  
Vol 175-176 ◽  
pp. 465-468 ◽  
Author(s):  
Lei Shi ◽  
Hua Wu Liu ◽  
Ping Xu ◽  
Dang Feng Zhao

Plain weave fabrics of polyacrylonitrile pre-oxidation yarns (PANOF) were prepared by small rapier loom. The flame retardation properties, mechanical properties and wear behaviors of PANOF plain weave fabrics were tested. The limiting oxygen index (LOI) of these PANOF plain weave fabric samples was 31%, which meets the criterion of flame-retardant fabrics. These fabrics neither melt nor shrunk when left in flame for a short period of time and the fabric structures were well maintained. Compared with flammable polyacrylonitrile fabrics, the polyacrylonitrile pre-oxidation fabrics exhibited excellent flame retardation properties, with satisfactory mechanical properties and comfortable handle.


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