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Liu, Peng
Publications (10 of 25) Show all publications
Geng, S., Shah, F. U., Liu, P., Antzutkin, O. & Oksman, K. (2017). Plasticizing and crosslinking effects of borate additives on the structure and properties of poly(vinyl acetate). RSC Advances, 7(13), 7483-7491
Open this publication in new window or tab >>Plasticizing and crosslinking effects of borate additives on the structure and properties of poly(vinyl acetate)
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2017 (English)In: RSC Advances, ISSN 2046-2069, E-ISSN 2046-2069, Vol. 7, no 13, p. 7483-7491Article in journal (Refereed) Published
Abstract [en]

As an environmentally friendly, low-cost and widely used polymer, poly(vinyl acetate) (PVAc) is worth modifying to achieve better properties. Here, we report on the influence of borate additives on the structure and properties of partially hydrolysed PVAc. In addition to the general crosslinking function of borate additives, an extraordinary plasticizing effect was found. By controlling the pH from 4 to 11 during sample preparation, the plasticizing and crosslinking effects can be shifted. In alkaline conditions, the degree of crosslinking in the PVAc/borate sample is increased; however, this increase declines gradually with an increase in the borate additive content, which impacts the morphology of the PVAc latex particles, as well as the mechanical and thermal properties of the PVAc/borate films. In contrast, in acidic conditions, the PVAc/borate films are plasticized by borate additives; thus, their ultimate mechanical strength, elastic moduli and thermal stabilities decrease, while the water diffusivities increase.

Place, publisher, year, edition, pages
Royal Society of Chemistry, 2017
National Category
Physical Chemistry Bio Materials
Research subject
Wood and Bionanocomposites; Chemistry of Interfaces
Identifiers
urn:nbn:se:ltu:diva-61616 (URN)10.1039/C6RA28574K (DOI)000393757100006 ()2-s2.0-85010648470 (Scopus ID)
Note

Validerad; 2017; Nivå 2; 2017-02-13 (andbra)

Available from: 2017-01-24 Created: 2017-01-24 Last updated: 2018-11-16Bibliographically approved
Liu, P., Garrido, B., Oksman, K. & Mathew, A. P. (2016). Adsorption isotherms and mechanisms of Cu(II) sorption onto TEMPO-mediated oxidized cellulose nanofibers. RSC Advances, 6(109), 107759-107767
Open this publication in new window or tab >>Adsorption isotherms and mechanisms of Cu(II) sorption onto TEMPO-mediated oxidized cellulose nanofibers
2016 (English)In: RSC Advances, ISSN 2046-2069, E-ISSN 2046-2069, Vol. 6, no 109, p. 107759-107767Article in journal (Refereed) Published
Abstract [en]

2,2,6,6-Tetramethyl-1-piperidinyloxy (TEMPO) mediated oxidized cellulose nanofibers (TOCNF) have shown potential in the removal of metal ions from contaminated water owing to their abundant carboxylate groups on their surface, functioning as metal sorption sites. The current work aims to study the kinetics and thermodynamics of the sorption behavior of Cu(II) onto TOCNF, and verify the correlation between Δ[H+] and the corresponding Δ[Cu(II)] in aqueous solution during sorption. Sorption of Cu(II) onto TOCNF was found to be an exothermic process with fast kinetics; reaching equilibrium Cu(II) adsorption in less than 1 min. The sorption data fits well with Langmuir isotherm models. The SEM imaging of the TOCNF after Cu(II) sorption revealed interesting copper-containing nanoparticles, which was further analyzed by using XRD. Besides, a linear correlation between Δ[H+] and the corresponding Δ[Cu(II)] in the solution was found, which indicates that the Cu(II) sorption capacity might be well predicted and calculated by Δ[H+] or pH variation during Cu(II) ion sorption onto TEMPO oxidized nanocellulose fibers and have potential to develop online sensors for tracking metal ion removal. 

National Category
Bio Materials
Research subject
Wood and Bionanocomposites
Identifiers
urn:nbn:se:ltu:diva-60566 (URN)10.1039/C6RA22397D (DOI)000389342400078 ()2-s2.0-84996554007 (Scopus ID)
Note

Validerad; 2017; Nivå 2; 2016-12-19 (andbra)

Available from: 2016-11-20 Created: 2016-11-20 Last updated: 2018-07-10Bibliographically approved
Geng, S., Noël, M., Liu, P. & Oksman, K. (2016). Cellulose-based nanocomposites with outstanding dispersion produced by in-situ polymerization (ed.). Paper presented at American Chemical Society (ACS) National Meeting & Exposition : 13/03/2016 - 17/03/2016. Paper presented at American Chemical Society (ACS) National Meeting & Exposition : 13/03/2016 - 17/03/2016.
Open this publication in new window or tab >>Cellulose-based nanocomposites with outstanding dispersion produced by in-situ polymerization
2016 (English)Conference paper, Oral presentation only (Refereed)
Abstract [en]

Cellulose-based nanocomposites are promising materials to replace the fossil-based polymers since they are biodegradable and produced from renewable resources. However, achieving good dispersion of nanocellulose in the matrix is one of the main obstacles because nanomaterials tend to form aggregates and lose their merits. In this study we developed an in-situ polymerization method to produce cellulose nanocrystals reinforced polyvinyl acetate, and the method of direct mechanical mixing was used as reference. The stability of in-situ and mixed nanocomposite aqueous dispersions was investigated by zeta potential measurements, and the results show that both of them were electrostatic stable at pH 4. Atomic force microscopy (AFM) and scanning electron microscopy (SEM) were used to characterize the dispersion of cellulose nanocrystals in the in-situ and mixed nanocomposites after drying, and better dispersion could be seen in the in-situ samples compared with the mixed ones. Tensile testing showed that the in-situ nanocomposites with same cellulose content had higher strength and longer elongation at break compared to the mixed nanocomposites. Furthermore, crosslinking the cellulose and partially hydrolyzed polyvinyl acetate with sodium tetraborate was also performed to further improved the reinforcing efficiency. The results from Raman spectroscopy illustrate that the heavy atoms (CC and CO) in cellulose experienced more stretching in the crosslinked nanocomposites, and the tensile testing indicated the elastic modulus and ultimate strength of them were increased significantly than those without crosslinking.

National Category
Bio Materials
Research subject
Wood and Bionanocomposites
Identifiers
urn:nbn:se:ltu:diva-31334 (URN)57c1b390-8309-46a3-8ce8-3ce137323856 (Local ID)57c1b390-8309-46a3-8ce8-3ce137323856 (Archive number)57c1b390-8309-46a3-8ce8-3ce137323856 (OAI)
Conference
American Chemical Society (ACS) National Meeting & Exposition : 13/03/2016 - 17/03/2016
Note
Godkänd; 2016; 20160331 (shigen)Available from: 2016-09-30 Created: 2016-09-30 Last updated: 2017-11-25Bibliographically approved
Liu, P., Oksman, K. & Mathew, A. P. (2016). Surface adsorption and self assembly of Cu(II) ions on TEMPO-oxidised cellulose nanofibers in aqueous media (ed.). Journal of Colloid and Interface Science, 464, 175-182
Open this publication in new window or tab >>Surface adsorption and self assembly of Cu(II) ions on TEMPO-oxidised cellulose nanofibers in aqueous media
2016 (English)In: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 464, p. 175-182Article in journal (Refereed) Published
Abstract [en]

TEMPO-mediated oxidized cellulose nanofibers (TOCNFs) have shown potential in the bioremediation of metal ions from contaminated water due to their interaction with positively charged metal ions via electrostatic interactions involving surface carboxyl groups. Copper is one of the most common pollutants in industrial effluents and is thus the target metal in the current study. The specific surface adsorption of Cu(II) was similar for TOCNFs with different degrees of functionalization and directly impacted the zeta potential. SEM imaging of the TOCNF after Cu(II) adsorption revealed interesting nanostructured clusters that were attributable to Cu(II) ions first being adsorbed by carboxylate groups on the TOCNF and subsequently being reduced and self-assembled to Cu(0) nanoparticles (NPs) or copper oxide NPs by microprecipitation. TOCNF turned superhydrophilic and resulted in faster water filtration after copper adsorption due to the stronger polarity of the copper ions or the self-assembled Cu(0) NPs creating voids or highly water-permeable channels at the interface between the interconnected TEMPO-oxidized nanofibers. Thus, the adsorption of Cu(II) ions and self-assembly into the Cu NPs on TOCNF favors a faster water purification process and provides a viable route to reuse/recycle TOCNFs studded with Cu nanoparticles as biocidal materials

National Category
Bio Materials
Research subject
Wood and Bionanocomposites
Identifiers
urn:nbn:se:ltu:diva-13570 (URN)10.1016/j.jcis.2015.11.033 (DOI)000367029600022 ()26619127 (PubMedID)2-s2.0-84947969635 (Scopus ID)cce58d4e-ff2f-4166-b444-27ef42136e42 (Local ID)cce58d4e-ff2f-4166-b444-27ef42136e42 (Archive number)cce58d4e-ff2f-4166-b444-27ef42136e42 (OAI)
Note

Validerad; 2015; Nivå 2; 20151008 (ajimat)

Available from: 2016-09-29 Created: 2016-09-29 Last updated: 2018-07-10Bibliographically approved
Liu, P. (2015). Adsorption behavior of heavy metal ions from aqueous medium on nanocellulose (ed.). (Doctoral dissertation). Paper presented at . : Luleå tekniska universitet
Open this publication in new window or tab >>Adsorption behavior of heavy metal ions from aqueous medium on nanocellulose
2015 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

The aim of this work was to explore the potential of nanocellulose, nanocellulose derivatives and nanochitin to remove metal ions from contaminated water. The above nano-polysaccharides were of interest in water purification technologies due to their high surface area and versatile surface chemistry. Silver, copper and iron are the primary metal ions targeted in the study, due to their abundance in industrial effluents. The first part of the study explored the potential of native nanocellulose and nanochitin isolated from bioresidues in removing silver ions from contaminated water. The highest Ag(I) removal for cellulose nanocrystals (CNC) was 34.4 mg/g, corresponding to 64 % removal ratio (CNC > ChNC > CNF). Wavelength dispersive X-ray analysis (WDX) and X-ray photoelectron spectroscopy (XPS) analysis confirmed the presence of silver ions on the surface of the nanocellulose and nanochitin after sorption. This study showed that the sorption performance is pH dependent and adsorption by cellulose nanocrystals was superior to cellulose nanofibers. The second part of the work focused on evaluating the surface adsorption enhancements after nanocellulose surface modifications viz. enzymatically phosphorylation and TEMPO-mediated oxidation. Both surface modifications dramatically improved the functionality and sorption capacity; a ten fold increase in Cu(II) adsorption was observed for TEMPO-mediated oxidized CNF compared to native CNF. Generally, when the mixture of metal ions were present in water the metal ion selectivity was in the order Ag(I) > Fe(III) > Cu(II), irrespective of the surface functionality of nanocellulose. Phosphorylated nanocelluloses demonstrated the capacity to reduce Cu(II) and Fe(III) concentrations in the effluent from mirror making industry to the level that meets WHO drinking water requirements. The increase in Cu(II) adsorption on TEMPO-mediated oxidized cellulose nanofibers (TOCNF) correlated both with the pH and carboxylate content and reached maximum values of 135 mg/g for highly oxidized cellulose. Furthermore, the Cu(II) could be easily recovered from the contaminated nanofibers through a washing procedure with acidic water. The adsorption capacity of TOCNF for other metal ions, such as Ni (II), Cr (III) and Zn (II), was also demonstrated. The third part of the work aimed at gaining deeper understanding of the Cu(II) sorption behavior onto TOCNF. The carboxylate groups introduced by TEMPO- oxidation on nanocellulose surface provided negatively charged sorption sites for Cu(II) ions. The metal sorption had fast kinetics (te < 20s) and increase in temperature lead to a mild decrease in Cu(II) sorption capacity. The equilibrium sorption data fitted well with Langmuir isotherms. Furthermore SEM analysis showed copper element-containing nanoparticles with a rather narrow size distribution on TOCNF, which opens up a new and a promising possibility of converting the TOCNF after Cu (II) adsorption into a variety of value-added products. TOCNF coupled with the adsorbed copper exhibited superhydrophilicity and decreased the filtration time for the TOCNF suspension after copper sorption. A linear correlation between Δ [H+] and the corresponding Δ [Cu(II)] in the solution during Cu(II) sorption was found and discussed. This work has demonstrated that nano-polysaccharides, particularly nanocellulose are highly promising biosorbents for scavenging metal ions from water and of great industrial relevance and may enable next-generation of water purification technologies.

Place, publisher, year, edition, pages
Luleå tekniska universitet, 2015
Series
Doctoral thesis / Luleå University of Technology 1 jan 1997 → …, ISSN 1402-1544
National Category
Bio Materials
Research subject
Wood and Bionanocomposites
Identifiers
urn:nbn:se:ltu:diva-26361 (URN)de630589-73fd-4f4e-8712-d1cf25eb33d6 (Local ID)978-91-7583-503-7 (ISBN)978-91-7583-504-4 (ISBN)de630589-73fd-4f4e-8712-d1cf25eb33d6 (Archive number)de630589-73fd-4f4e-8712-d1cf25eb33d6 (OAI)
Note
Godkänd; 2015; 20151204 (pengliu); Nedanstående person kommer att disputera för avläggande av teknologie doktorsexamen. Namn: Peng Liu Ämne: Trä- och bionanokompositer/Wood and Bionanocomposites Avhandling: Adsorption Behavior of heavy metal ions from aqueous medium on nanocellulose Opponent: Professor Lars Wågberg, Institutionen för fiber och polymerteknologi, Skolan för kemivetenskap, KTH, Stockholm Ordförande: Bitr professor Aji Mathew, Avd för materialvetenskap, Institutionen för teknikvetenskap och matematik, Luleå tekniska universitet, Luleå Tid: Torsdag 21 januari 2016, kl 10.00 Plats: Luleå tekniska universitet, sal E632Available from: 2016-09-30 Created: 2016-09-30 Last updated: 2017-11-24Bibliographically approved
Liu, P., Mathew, A. P. & Oksman, K. (2015). Adsorption Characteristics of Cu2+ from Aqueous Medium onto TEMPO oxidised cellulose nanofibers (TOCNF) (ed.). In: (Ed.), : . Paper presented at Dissemenation Workshop for the Nano4water Cluster : 20/01/2015 - 21/10/2015.
Open this publication in new window or tab >>Adsorption Characteristics of Cu2+ from Aqueous Medium onto TEMPO oxidised cellulose nanofibers (TOCNF)
2015 (English)Conference paper, Oral presentation only (Refereed)
National Category
Bio Materials
Research subject
Wood and Bionanocomposites
Identifiers
urn:nbn:se:ltu:diva-26826 (URN)0147ba0c-283c-4d47-a027-19686b141041 (Local ID)0147ba0c-283c-4d47-a027-19686b141041 (Archive number)0147ba0c-283c-4d47-a027-19686b141041 (OAI)
Conference
Dissemenation Workshop for the Nano4water Cluster : 20/01/2015 - 21/10/2015
Note

Godkänd; 2015; 20151008 (ajimat)

Available from: 2016-09-30 Created: 2016-09-30 Last updated: 2017-11-25Bibliographically approved
Liu, P., Mathew, A. P. & Oksman, K. (2015). Adsorption study of Cu(II) ions onto TEMPO oxidised cellulose nanofibers (TOCNF) (ed.). In: (Ed.), : . Paper presented at International Polysaccharide Conference : 18/10/2015 - 22/10/2015.
Open this publication in new window or tab >>Adsorption study of Cu(II) ions onto TEMPO oxidised cellulose nanofibers (TOCNF)
2015 (English)Conference paper, Oral presentation only (Refereed)
National Category
Bio Materials
Research subject
Wood and Bionanocomposites
Identifiers
urn:nbn:se:ltu:diva-37012 (URN)ae2fbf2f-5fac-4083-8ed7-2f56b303c2d0 (Local ID)ae2fbf2f-5fac-4083-8ed7-2f56b303c2d0 (Archive number)ae2fbf2f-5fac-4083-8ed7-2f56b303c2d0 (OAI)
Conference
International Polysaccharide Conference : 18/10/2015 - 22/10/2015
Note
Godkänd; 2015; 20151008 (ajimat)Available from: 2016-10-03 Created: 2016-10-03 Last updated: 2017-11-25Bibliographically approved
Liu, P., Mathew, A. P. & Oksman, K. (2015). Multifunctional materials for environmental applications based on TEMPO-oxidized cellulose nanofibers (TOCNF) (ed.). In: (Ed.), : . Paper presented at Marcus Wallenberg Prize Ceremony : 28/09/2015 - 30/09/2015.
Open this publication in new window or tab >>Multifunctional materials for environmental applications based on TEMPO-oxidized cellulose nanofibers (TOCNF)
2015 (English)Conference paper, Oral presentation only (Refereed)
National Category
Bio Materials
Research subject
Wood and Bionanocomposites
Identifiers
urn:nbn:se:ltu:diva-37636 (URN)bb5e6744-a661-49b8-9226-202557ab0b0d (Local ID)bb5e6744-a661-49b8-9226-202557ab0b0d (Archive number)bb5e6744-a661-49b8-9226-202557ab0b0d (OAI)
Conference
Marcus Wallenberg Prize Ceremony : 28/09/2015 - 30/09/2015
Note

Godkänd; 2015; 20151008 (ajimat)

Available from: 2016-10-03 Created: 2016-10-03 Last updated: 2017-11-25Bibliographically approved
Liu, P., Borrell, P. F., Božič, M., Kokol, V., Oksman, K. & Mathew, A. P. (2015). Nanocelluloses and their phosphorylated derivatives for selective adsorption of Ag+, Cu2+ and Fe3+ from industrial effluents (ed.). Paper presented at . Journal of Hazardous Materials, 294, 177-185
Open this publication in new window or tab >>Nanocelluloses and their phosphorylated derivatives for selective adsorption of Ag+, Cu2+ and Fe3+ from industrial effluents
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2015 (English)In: Journal of Hazardous Materials, ISSN 0304-3894, E-ISSN 1873-3336, Vol. 294, p. 177-185Article in journal (Refereed) Published
Abstract [en]

The potential of nanoscaled cellulose and enzymatically phosphorylated derivatives as bio-adsorbents to remove metal ions (Ag+, Cu2+ and Fe3+) from model water and industrial effluents is demonstrated. Introduction of phosphate groups onto nanocelluloses significantly improved the metal sorption velocity and sorption capacity. The removal efficiency was considered to be driven by the high surface area of these nanomaterials as well as the nature and density of functional groups on the nanocellulose surface. Generally, in the solutions containing only single types of metal ions, the metal ion selectivity was in the order Ag+ > Cu2+ > Fe3+, while in the case of mixtures of ions, the order changed to Ag+ > Fe3+ > Cu2+, irrespective of the surface functionality of the nanocellulose. In the case of industrial effluent from the mirror making industry, 99% removal of Cu2+ and Fe3+ by phosphorylated nanocellulose was observed. The study showed that phosphorylated nanocelluloses are highly efficient biomaterials for scavenging multiple metal ions, simultaneously, from industrial effluents.

National Category
Bio Materials
Research subject
Wood and Bionanocomposites
Identifiers
urn:nbn:se:ltu:diva-15403 (URN)10.1016/j.jhazmat.2015.04.001 (DOI)000355028700021 ()25867590 (PubMedID)2-s2.0-84926462440 (Scopus ID)ee903f3d-7ce7-452b-a59e-a6a3753becd5 (Local ID)ee903f3d-7ce7-452b-a59e-a6a3753becd5 (Archive number)ee903f3d-7ce7-452b-a59e-a6a3753becd5 (OAI)
Note
Validerad; 2015; Nivå 2; 20150407 (andbra)Available from: 2016-09-29 Created: 2016-09-29 Last updated: 2018-07-10Bibliographically approved
Geng, S., Noël, M., Liu, P. & Oksman, K. (2015). Single-step method for producing cellulose based nanocomposites with outstanding dispersion (ed.). Paper presented at Marcus Wallenberg Prize Event – Young Researchers’ Challenge 2015 : 28/09/2015 - 30/09/2015. Paper presented at Marcus Wallenberg Prize Event – Young Researchers’ Challenge 2015 : 28/09/2015 - 30/09/2015.
Open this publication in new window or tab >>Single-step method for producing cellulose based nanocomposites with outstanding dispersion
2015 (English)Conference paper, Poster (with or without abstract) (Refereed)
Abstract [en]

Cellulose nanomaterials are promising as reinforcement in composites, which is attributed to high mechanical properties, generating large interfacial area and biodegradable ability, etc. However, obtaining good dispersion is a main challenge of large-scale industrial applications since nanomaterials tend to form aggregates and lose their merits. In this study we developed a single-step method that is in-situ polymerization to produce cellulose nanocrystals reinforced polyvinyl acetate with good dispersion. Compared to normal composites prepared by direct mechanical mixing, better dispersion of cellulose nanocrystals by using in-situ polymerization has been confirmed by atomic force microscopy. Mechanical testing shown that the in-situ nanocomposites with same cellulose content had higher strength and longer elongation at break compared to direct mixed composites. Moreover, crosslinks between cellulose and partially hydrolysed polyvinyl acetate could be formed by tetrahydroborate ions in aqueous dispersion, which further improved the reinforcing efficiency. The cellulose based nanocomposites produced by in-situ polymerization are potential materials to replace fossil based polymers used in packaging and coating applications.

National Category
Bio Materials
Research subject
Wood and Bionanocomposites
Identifiers
urn:nbn:se:ltu:diva-35289 (URN)9c261215-c6c5-4608-b96c-cf2abe26f6a4 (Local ID)9c261215-c6c5-4608-b96c-cf2abe26f6a4 (Archive number)9c261215-c6c5-4608-b96c-cf2abe26f6a4 (OAI)
Conference
Marcus Wallenberg Prize Event – Young Researchers’ Challenge 2015 : 28/09/2015 - 30/09/2015
Note
Godkänd; 2015; 20160331 (shigen)Available from: 2016-09-30 Created: 2016-09-30 Last updated: 2017-11-25Bibliographically approved
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