scholarly journals Properties Enhancement of High Molecular Weight Polylactide Using Stereocomplex Polylactide as a Nucleating Agent

Polymers ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1725
Author(s):  
Purba Purnama ◽  
Muhammad Samsuri ◽  
Ihsan Iswaldi

As one of the most attractive biopolymers nowadays in terms of their sustainability, degradability, and material tune-ability, the improvement of polylactide (PLA) homopolymer properties by studying the utilization of stereocomplex polylactide (s-PLA) effectively and efficiently is needed. In this sense, we have studied the utilization of s-PLA compared to poly D-lactide (PDLA) homopolymers as a nucleating agent for PLA homopolymers. The mechanical and thermal properties and crystallization behavior of PLA homopolymers in the presence of nucleating agents have been evaluated using a universal testing machine, differential scanning calorimeter, and X-ray diffractometer instruments, respectively. PDLA and s-PLA materials can be used to increase the thermal and mechanical properties of poly L-lactide (PLLA) homopolymers. The s-PLA materials increased the mechanical properties by increasing crystallinity of the PLLA homopolymers. PLLA/s-PLA enhanced mechanical properties to a certain level (5% s-PLA content), then decreased them due to higher s-PLA materials affecting the brittleness of the blends. PDLA homopolymers increased mechanical properties by forming stereocomplex PLA with PLLA homopolymers. Non-isothermal and isothermal evaluation showed that s-PLA materials were more effective at enhancing PLLA homopolymer properties through nucleating agent mechanism.

2013 ◽  
Vol 746 ◽  
pp. 203-210
Author(s):  
E. Budianto ◽  
M. Anggaravidya ◽  
Sudirman ◽  
C. Liza ◽  
B. Soegijono ◽  
...  

In order to improve the mechanical properties of natural rubber so it can be used as raw material for industrial component, it is required to add filler and coupling agent to the natural rubber. In previous study, carbon black obtained from sonofication process for 3 and 5 hours was added (filled) to improve thermal and mechanical properties of rubber-carbon black, where the improvement was influenced by the period of sonofication of carbon black, which subsequently added to the rubber-carbon black composite.In this study, various rubber-carbon composites have been synthesized using thin pale crepe (TPC) natural rubber as matrix, strengthened by carbon black N 660, sonoficated N 660, and addition of 2 phr of 3-aminopropyltriethoxysilane (APTS) to each composite. The obtained rubber-carbon black composite was characterized by using Fourier Transform Infrared Spectroscopy (FTIR) and Scanning Electron Microscopy-Energy Dispersive X-Ray Spectroscopy (SEM-EDS). Universal Testing Machine was used to characterize its mechanical properties.Bound rubber value and mechanical properties of rubber-carbon black composite improved as a result of the addition of carbon black obtained from sonofication and APTS. However, contrast result was observed when sonoficated carbon black and APTS were added simultaneously.


2012 ◽  
Vol 624 ◽  
pp. 264-268 ◽  
Author(s):  
Duo You Zhang ◽  
Peng Liu ◽  
Chun Fa Ouyoung ◽  
Qun Gao ◽  
Kang Sheng Zheng ◽  
...  

PNA012 is a new nucleating agent on polybutylene terephthalate. The effect of different dosage of PNA012 on crystallization and mechanical properties were investigated by means of differential scanning calorimetry, universal testing machine, melt flow indexer and vicat softening testing machine. It was revealed that the PNA012 could substantially accelerate the crystallization of PBT. Compared with the pure PBT,the crystallization temperature of PBT/PNA012 rises from 196.3 °C to 199.7 °C and crystallization degree from 34.2% to 39.9%. The tensile Strength of PBT/PNA012 is increased 9.7%. The Bending Strength has a rise of 9.3% and the heat distortion temperatures of PBT/PNA012 is increased from 115.07°C to 125.94°C.


2013 ◽  
Vol 807-809 ◽  
pp. 578-581 ◽  
Author(s):  
Jin Xu Dai ◽  
Qiang Yang ◽  
Bao Jian Liu

A series of PLA blends were prepared by solution co-precipitation of polylactide (PLA), polyethylene glycol (PEG) and different crystallization nucleating agents. The crystallization behavior of blends was investigated by differential scanning calorimeter (DSC) and X-ray diffraction (XRD). The results showed that the crystallization ability of PLA blends was accelerated by plasticizer PEG, but the crystal structure of the obtained PLA blends was imperfect; the crystal structure and crystallization rate of the PLA blends were improved with the addition of nucleating agent, moreover, the crystallinity was 34.1% and 36.5%, respectively.


2011 ◽  
Vol 311-313 ◽  
pp. 1332-1335
Author(s):  
Hao Lv ◽  
Yao Ming Ding ◽  
Ai Mei Liu ◽  
Ju Fang Tong ◽  
Xu Nong Yi ◽  
...  

The nucleation and crystallization of Li2O-Al2O3-SiO2(LAS) glass ceramic with one(P2O5, TiO2, ZnF2) and two nucleating agents(P2O5+TiO2, P2O5+ZnF2) are investigated by the differential thermal analysis(DTA),X-ray diffraction(XRD) and the scanning electron microscopy(SEM). Research results show that the LAS glass ceramic with nucleating agent of P2O5can obtain ideal micro spherical crystal grains and the crystallization behavior can be better controlled.


2013 ◽  
Vol 747 ◽  
pp. 174-177 ◽  
Author(s):  
Waraporn Suvannapruk ◽  
Faungchat Thammarakcharoen ◽  
Watchara Chokevivat ◽  
Pattaravit Rukskul ◽  
Jintamai Suwanprateeb

In this study, four types of PEG-PPG-PEG copolymers solids and pastes having different molecular mass (Mw~5800, 8400, 12000 and 14600) were selected and mixed at various compositions ranging from 40 to 60 % by weight. The textures and handling characteristics of the prepared samples were evaluated in comparison to that of the commercial non-resorbable bone wax. Thermal and mechanical properties of the blends were determined by a differential scanning calorimeter and a universal testing machine respectively. It was found that the combination of solid (Mw~8400) and paste-like (Mw~12000) copolymers at the ratio of 40:60 gave the closest smooth texture with good smearability and had similar melting temperature to the commercial bone wax, but having slightly lower compressive stiffness. Preliminary cytotoxicity of the selected formulations against osteoblasts revealed that the cell viability was greater than 70 % indicating that the prepared samples did not show any cytotoxic potential.


e-Polymers ◽  
2019 ◽  
Vol 19 (1) ◽  
pp. 32-39 ◽  
Author(s):  
Yanjie An ◽  
Sihan Wang ◽  
Rui Li ◽  
Dezhu Shi ◽  
Yuxin Gao ◽  
...  

AbstractThe effects of phosphate nucleating agent (NA), carboxylate nucleating agent (MD), rosin type nucleating agent (WA) and sorbitol nucleating agent (NX) on crystallization behavior of isotactic polypropylene were investigated by fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), differential scanning calorimetry (DSC) and polarized light microscopy (PLM). The results showed that different structure nucleating agents significantly affected the crystallization kinetics, rate and temperature of polypropylene. Among them, half crystallization time of NX nucleating agent was the shortest, which was 53.4 seconds, and the crystallization temperature was the highest, reaching 129.8°C.


Polymers ◽  
2021 ◽  
Vol 13 (12) ◽  
pp. 2018
Author(s):  
Muhammad Samsuri ◽  
Ihsan Iswaldi ◽  
Purba Purnama

Stereocomplexation is one of several approaches for improving polylactide (PLA) properties. The high molecular weight of poly L-lactide (PLLA) and poly D-lactide (PDLA) homopolymers are a constraint during the formation of stereocomplex PLAs (s-PLAs). The presence of s-PLA particles in PLA PLLA/PDLA blends can initiate the formation of s-PLA crystalline structures. We used the solution casting method to study the utilization of s-PLA materials from high molecular weight PLLA/PDLA blends for increasing s-PLA formation. The s-PLA particles initiated the formation of high molecular weight PLLA/PDLA blends, obtaining 49.13% s-PLA and 44.34% of the total crystalline fraction. In addition, the mechanical properties were enhanced through s-PLA crystalline formation and the increasing of total crystallinity of the PLLA/PDLA blends. The s-PLA particles supported initiation for s-PLA formation and acted as a nucleating agent for PLA homopolymers. These unique characteristics of s-PLA particles show potential to overcome the molecular weight limitation for stereocomplexation of PLLA/PDLA blends.


2021 ◽  
pp. 095400832199676
Author(s):  
Yuting Ouyang ◽  
Qiu Zhang ◽  
Xiukun Liu ◽  
Ruan Hong ◽  
Xu Xu ◽  
...  

Different ionic liquid modified graphene nanosheets (IG) were induced into polyimide (PI) to improve the tribological, thermal, and mechanical properties of shape memory IG/PI composites. The results demonstrated that when using 1-aminoethyl-3-methylimidazole bromide to modify graphene nanosheets (IG-1), the laser-driven shape recovery rate of IG-1/PI composites (IGPI-1) reached 73.02%, which was 49.36% higher than that of pure PI. In addition, the IGPI-1 composite materials reached the maximum shape recovery rate within 15 s. Additionally, under dry sliding, the addition of IG can significantly improve the tribological properties of composite materials. IGPI-1 exhibited the best self-lubricating properties. Compared with pure PI, the friction coefficient (0.19) and wear rate (2.62 × 10–5) mm3/Nm) were reduced by 44.1% and 24.2%, respectively, and the T10% of IGPI-1 increased by 32.2°C. The Tg of IGPI-1 reached 256.5°C, which was 8.4°C higher than that of pure PI. In addition, the tensile strength and modulus of IGPI-1 reached 82.3 MPa and 1.18 GPa, which were significantly increased by 33.6% and 29.8%, respectively, compared with pure PI. We hope that this work will be helpful for the preparation of shape memory materials with excellent tribological, thermal, and mechanical properties.


Materials ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1303
Author(s):  
Michael Seidenstuecker ◽  
Thomas Schmeichel ◽  
Lucas Ritschl ◽  
Johannes Vinke ◽  
Pia Schilling ◽  
...  

This work aimed to determine the influence of two hydrogels (alginate, alginate-di-aldehyde (ADA)/gelatin) on the mechanical strength of microporous ceramics, which have been loaded with these hydrogels. For this purpose, the compressive strength was determined using a Zwick Z005 universal testing machine. In addition, the degradation behavior according to ISO EN 10993-14 in TRIS buffer pH 5.0 and pH 7.4 over 60 days was determined, and its effects on the compressive strength were investigated. The loading was carried out by means of a flow-chamber. The weight of the samples (manufacturer: Robert Mathys Foundation (RMS) and Curasan) in TRIS solutions pH 5 and pH 7 increased within 4 h (mean 48 ± 32 mg) and then remained constant over the experimental period of 60 days. The determination surface roughness showed a decrease in the value for the ceramics incubated in TRIS compared to the untreated ceramics. In addition, an increase in protein concentration in solution was determined for ADA gelatin-loaded ceramics. The macroporous Curasan ceramic exhibited a maximum failure load of 29 ± 9.0 N, whereas the value for the microporous RMS ceramic was 931 ± 223 N. Filling the RMS ceramic with ADA gelatin increased the maximum failure load to 1114 ± 300 N. The Curasan ceramics were too fragile for loading. The maximum failure load decreased for the RMS ceramics to 686.55 ± 170 N by incubation in TRIS pH 7.4 and 651 ± 287 N at pH 5.0.


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