Dimensional stabilisation of Scots pine (Pinus sylvestris L.) sapwood by reaction with maleic anhydride and sodium hypophosphite

European Journal of Wood and Wood Products ◽

10.1007/s00107-020-01650-6 ◽

2021 ◽

Author(s):

Injeong Kim ◽

Olov Karlsson ◽

Dennis Jones ◽

George Mantanis ◽

Dick Sandberg

Keyword(s):

Maleic Anhydride ◽

Chemical Modification ◽

Scots Pine ◽

Dimensional Stability ◽

Hydrolytic Stability ◽

Treatment Temperature ◽

Sodium Hypophosphite ◽

Cross Linking ◽

High Concentration ◽

Weight Percentage

AbstractWood has the ability to absorb and desorb moisture, which can affect its dimensional size when in use. Limiting this can provide products with greater shape stability and less stresses on external coatings. One method that has been investigated for achieving this has been through chemical modification. In this work, the dimensional stabilisation imparted to Scots pine sapwood by chemical modification with maleic anhydride (MA) combined with sodium hypophosphite (SHP) was investigated. The influence of concentration of MA, treatment temperature and treatment period on weight percent gain (WPG) and bulking coefficient (BC) during treatment with MA and SHP of wood was studied. Furthermore, dimensional stability was determined by the water soak/oven dry method (wet-dry cycle) through five cycles in order to determine the hydrolytic stability of the ester bond and any potential cross-linking reactions. Wood blocks (20 × 20 × 10 mm) modified with MA combined with SHP exhibited lower weight loss following water soaking than unmodified blocks or MA-treated blocks. Wood blocks modified with MA and SHP showed the best anti-swelling efficiency and minimum wet-volume (water-saturated). However, as the concentration of SHP increased, dimensional stability was diminished without any increase in weight percentage gain after water soaking. When combined with FTIR results, it appeared that the modification with MA and SHP seemed to form cross-linking between wood constituents, though high concentration of SHP did not seem to result in additional cross-linking.

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Chemical Modification of Wood by Polyglycerol/Maleic Anhydride Treatment

Holzforschung ◽

10.1515/hf.2001.009 ◽

2001 ◽

Vol 55 (1) ◽

pp. 57-62 ◽

Cited By ~ 11

Author(s):

C. Roussel ◽

V. Marchetti ◽

A. Lemor ◽

E. Wozniak ◽

B. Loubinoux ◽

...

Keyword(s):

Maleic Anhydride ◽

Chemical Modification ◽

Aqueous Solutions ◽

Dimensional Stability ◽

Treated Wood ◽

Solid Wood ◽

Reaction Conditions ◽

Biological Resistance ◽

Long Time ◽

And Performance

Summary Polyglycerol (PG), an agricultural by-product of diester industry, was reacted with maleic anhydride (MA) to give heat curable compounds which are useful for impregnating wood to improve biological resistance, dimensional stability and strength. The relationships between reaction conditions of polyglycerol/maleic anhydride (PG/MA) adduct treatment and performance of treated solid wood were investigated. Conditions recommended for producing PG/MA treated wood durable for a long time are vacuum/pressure impregnation of aqueous solutions of PG/MA adduct (30%) in the presence of 2-butanone peroxide (2%) and cobalt naphthenate (2%).

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Characterisation of Moisture in Scots Pine (Pinus sylvestris L.) Sapwood Modified with Maleic Anhydride and Sodium Hypophosphite

Forests ◽

10.3390/f12101333 ◽

2021 ◽

Vol 12 (10) ◽

pp. 1333

Author(s):

Injeong Kim ◽

Emil Engelund Thybring ◽

Olov Karlsson ◽

Dennis Jones ◽

George I. Mantanis ◽

...

Keyword(s):

Cell Wall ◽

Maleic Anhydride ◽

Scots Pine ◽

Cell Walls ◽

Sodium Hypophosphite ◽

Hydroxyl Groups ◽

Capillary Water ◽

Saturated State ◽

Water Saturated ◽

Modified Wood

In this study, the wood–water interactions in Scots pine sapwood modified with maleic anhydride (MA) and sodium hypophosphite (SHP) was studied in the water-saturated state. The water in wood was studied with low field nuclear magnetic resonance (LFNMR) and the hydrophilicity of cell walls was studied by infrared spectroscopy after deuteration using liquid D2O. The results of LFNMR showed that the spin–spin relaxation (T2) time of cell wall water decreased by modification, while T2 of capillary water increased. Furthermore, the moisture content and the amount of water in cell walls of modified wood were lower than for unmodified samples at the water-saturated state. Although the amount of accessible hydroxyl groups in modified wood did not show any significant difference compared with unmodified wood, the increase in T2 of capillary water indicates a decreased affinity of the wood cell wall to water. However, for the cell wall water, the physical confinement within the cell walls seemed to overrule the weaker wood–water interactions.

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Effect of chemical modification and heat treatment on biological durability and dimensional stability of Pinus roxburghii Sarg.

New Zealand Journal of Forestry Science ◽

10.33494/nzjfs512021x143x ◽

2021 ◽

Vol 51 ◽

Author(s):

Ajmal Samani ◽

Sauradipta Ganguly ◽

Sanjeet Kumar Hom

Keyword(s):

Heat Treatment ◽

Citric Acid ◽

Chemical Modification ◽

Dimensional Stability ◽

Water Solution ◽

Brown Rot ◽

Wood Preservation ◽

Sodium Hypophosphite ◽

Pinus Roxburghii ◽

Biological Durability

Background: Depleting supplies of wood species with inherent natural durability has resulted in the focus being shifted to non-durable plantation grown and imported timber. Despite its abundant availability and better treatability, the use of Pinus roxburghii is limited to packing cases, crates, shutters, door and window frame, carpentry and joinery items due to its nondurable nature. Hence, to promote use of such timber for applications such as decking, cladding and facade elements chemical modification with a combination of citric acid and sodium hypophosphite, and heat treatment were explored to improve its service life. Methods: Chemical modification was performed using a water solution of citric acid (6.9%) and sodium hypophosphite (6.5%) followed by curing at 140°C for 8 hrs. Dimensional stability was determined by estimating the volumetric swelling coefficient and anti-swelling efficiency (ASE) of treated and control samples. Durability against fungus and termites was evaluated using a soil block bioassay and termite mound test as per standard methods. Results: Both chemical modification and heat treatment of P. roxburghii resulted in enhanced dimensional stability and biological durability compared to the untreated controls. Chemical modification and heat treatment resulted in 23.05% and 18.37% volumetric ASE, respectively. Results showed that a highly perishable species became significantly more durable after chemical modification, exhibiting 5–6 times less mass loss by termites in comparison to the controls. Wood samples modified with citric acid showed excellent resistance to both white and brown rot fungi and exhibited 14-15 times less reduction in mass compared with untreated samples. Conclusions: Citric acid chemical modification is an environment friendly process that improved the dimensional stability as well as resistance against biodegradation. These studies may provide valuable inputs to establish this mode of chemical modification as a cost-effective alternative to other chemicals for wood preservation. The concentrations of the chemicals and temperature for fixation may be varied to establish an optimum combination for best output.

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Double-Cross-Linked Networks Based on Methacryloyl Mucin

Polymers ◽

10.3390/polym13111706 ◽

2021 ◽

Vol 13 (11) ◽

pp. 1706

Author(s):

Elena Olăreț ◽

Brîndușa Bălănucă ◽

Andra Mihaela Onaș ◽

Jana Ghițman ◽

Horia Iovu ◽

...

Keyword(s):

Mechanical Properties ◽

Aqueous Solution ◽

Chemical Modification ◽

Structural Modification ◽

Aqueous Media ◽

Cross Linking ◽

Ph Values ◽

Acid Aqueous Solution ◽

Reaction Media ◽

Double Cross

Mucin is a glycoprotein with proven potential in the biomaterials field, but its use is still underexploited for such applications. The present work aims to produce a synthesis of methacryloyl mucin single-network (SN) hydrogels and their double-cross-linked-network (DCN) counterparts. Following the synthesis of the mucin methacryloyl derivative, various SN hydrogels are prepared through the photopolymerization of methacrylate bonds, using reaction media with different pH values. The SN hydrogels are converted into DCN systems via supplementary cross-linking in tannic acid aqueous solution. The chemical modification of mucin is described, and the obtained product is characterized; the structural modification of mucin is assessed through FTIR spectroscopy, and the circular dichroism and the isoelectric point of methacryloyl mucin is evaluated. The affinity for aqueous media of both SN and DCN hydrogels is estimated, and the mechanical properties of the systems are assessed, both at macroscale through uniaxial compression and rheology tests and also at microscale through nanoindentation tests.

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Chemical modification and cross-linking as probes of regions on ferredoxin involved in its interaction with ferredoxin: NADP reductase

Biochimica et Biophysica Acta (BBA) - Bioenergetics ◽

10.1016/0005-2728(86)90254-9 ◽

1986 ◽

Vol 851 (1) ◽

pp. 109-122 ◽

Cited By ~ 30

Author(s):

Barbara J. Vieira ◽

Kim K. Colvert ◽

Danny J. Davis

Keyword(s):

Chemical Modification ◽

Cross Linking

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Chemical Modification of Butyl Rubber with Maleic Anhydride via Nitroxide Chemistry and Its Application in Polymer Blends

Polymers ◽

10.3390/polym9020063 ◽

2017 ◽

Vol 9 (12) ◽

pp. 63 ◽

Cited By ~ 4

Author(s):

José Bonilla-Cruz ◽

Brenda Hernández-Mireles ◽

Ricardo Mendoza-Carrizales ◽

Luis Ramírez-Leal ◽

Román Torres-Lubián ◽

...

Keyword(s):

Maleic Anhydride ◽

Chemical Modification ◽

Polymer Blends ◽

Butyl Rubber

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Dimensional Stability of Poplar Wood after Densification Combined with Heat Treatment

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.152-154.112 ◽

2012 ◽

Vol 152-154 ◽

pp. 112-116 ◽

Cited By ~ 2

Author(s):

Jia Bin Cai ◽

Tao Ding ◽

Liu Yang

Keyword(s):

Heat Treatment ◽

Dimensional Stability ◽

Hybrid Poplar ◽

Treatment Temperature ◽

Thermal Modification ◽

Holding Time ◽

Poplar Wood ◽

Compression Set ◽

Densification Temperature

Hybrid poplar boards were subjected to thermo-mechanical densification combined with heat treatment. Hydroscopicity and hygroscopicity of the treated samples were measured. The results showed that dimensional stability of the samples was influenced by compression set significantly. The higher the compression set, the greater the swelling of the samples. On the contrary, the influence of densification temperature and duration was not significant. Thermal modification significantly reduced hydroscopicity and hygroscopicity of the samples. Both higher treatment temperature and longer holding time resulted in better dimensional stability.

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Improvement in Mechanical Properties of High Concentration Particle Doped Thermoset Composites

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.442.335 ◽

2010 ◽

Vol 442 ◽

pp. 335-341

Author(s):

N. Ahmed ◽

Mohammad Bilal Khan

Keyword(s):

Mechanical Properties ◽

Thermal Response ◽

Chain Extension ◽

Cross Linking ◽

High Concentration ◽

Viscoelastic Composite ◽

Thermoset Composites ◽

Storage And Loss Moduli ◽

Base Polymer ◽

Sequential Addition

The paper relates to high concentration particle doped composites based on thermosetting polymer systems in which the sequential addition of particles of certain size distribution is followed by curing and casting of the slurry to form a thermoset composite. Conventionally, at a threshold of beyond 90% of particles by weight of the polymer using triglyceride, the mechanical properties of the composite exhibit a sharp decline. The present research mitigates this behavior by incorporating a unique combination of cross-linking agents in the base polymer to impart exceptional mechanical properties to the composite. More specifically, the base polymer consists of butadiene, with triglyceride as cross-linking agent together with hydroxy-alkane as the chain extension precursors, when tune to the appropriate level of hard segment ratio in the polymer. An added advantage according to the present work resides in the analytical nature of butadiene pre-polymer as opposed to natural product; traditional composites based on natural sources are hampered by their inconsistent chemical composition and poor shelf life in the fabricated composite. The thermoset composite according the present research exhibits superior tensile strength (200-300 psi) properties using particle loading as high as 92% by weight of the fabricated composite as measured on a Tinius Olsen machine. Dynamic Mechanical Testing reveals interesting combination of storage and loss moduli in the fabricated specimens as a function of optimizing the thermal response of the viscoelastic composite to imposed vibration loading.

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