نتایج جستجو برای: quebracho tannin wood adhesive in non formaldehyde approach has low autocondensation rate and needs more press time than formaldehyde
تعداد نتایج: 22200394 فیلتر نتایج به سال:
To prepare a low-formaldehyde soy-based adhesive with good water resistance, phenol-formaldehyde modified with glutaraldehyde (PFG) with lower free phenol and free formaldehyde contents was used to cross-link the soy-based adhesive. The results showed that the mechanical properties and water resistance of plywood prepared with soy-based adhesive with PFG was better than that of plywood with the...
The development of natural-based adhesives is a key aspect in reducing the consumption fossil resources, adapting to legislation on use formaldehyde and ensuring sustainability wood panel industry. This study focuses five alternatives for tannin-based (tannin-paraformaldehyde, tannin-glyoxal, tannin-hexamine, tannin non-isocyanate polyurethane (NIPU) with ammonium hydroxide NIPU HDMA bio-adhesi...
Acetylation of wood imparts moisture durability, decay resistance, and dimensional stability to wood; however, making durable adhesive bonds with acetylated wood can be more difficult than with unmodified wood. The usual explanation is that the acetylated surface has fewer hydroxyl groups, resulting in a harder-to-wet surface and in fewer hydrogen bonds between wood and adhesive. This concept w...
The reaction of a tannin extract (containing about 30"/0 carbohydrate) from loblolly pine (Pinus taeda L.) bark (two parts) and resorcinol (one part) at 12O"C for 24 h with acetic acid catalyst gave a product containing predominantly oligomeric procyanidin-4-resorcinol adducts (3Wo), unreacted resorcinol (22%). carbohydrate (20010). the resorcinol adduct 2R,3R,4S 4-(2.4-dihydroxyphenyl).fIavan-...
The effects on silage composition of ensiling perennial ryegrass (PRG) with three commercial tannins (mimosa, myrabolam and quebracho tannins) were assessed (Experiment 1). The effects on silage composition and mobile bag disappearance of DM, nitrogen and true protein of the addition of these tannins or a combination of tannin plus formic acid, formaldehyde alone, formic acid alone, or a combin...
abstract this study investigated the predictability of variables from a motivational framework as well as individuals qualities to predict three non-linguistic outcomes of language learning. gardners socio-educational model with its measures has been used in the current study. individual qualities presented in this study include (1) age, (2) gender, and (3) language learning experience. the...
in this study, the effects of oleothermal modification on physical and mechanical peroperties of fir wood (abeis sp.) blocks were examined. at first, some blocks of fir wood with 5 × 20 × 120 cm dimensions were prepared. the blocks were treated in soybean oil. the effects of 3 factors such as treatments temperature (180and 200 °c), holding time (12 and 15 h) and initial moisture content of wood...
abstract: about 60% of total premium of insurance industry is pertained?to life policies in the world; while the life insurance total premium in iran is less than 6% of total premium in insurance industry in 2008 (sigma, no 3/2009). among the reasons that discourage the life insurance industry is the problem of adverse selection. adverse selection theory describes a situation where the inf...
drought is transient phenomenon , slow , repetitive and integral part of the climate of each region. drought begins with a substantial reduction in precipitation over the long-term average rainfall and over time, reduced soil moisture and surface and ground water resources will continue to decrease. this phenomenon is the most important in bakhtegan basin because of its importance in strategic ...
a large number of single research studies on the effects of strategy-based instruction (sbi) in teaching english as a foreign or second language has been conducted so far. however, the lack of a comprehensive meta-analysis targeting the effectiveness of english language sbi is observed. moreover, the findings of experimental studies regarding the context of the english language, proficiency lev...
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