The synthesis of bromo derivatives cardanolic novolac resins (BCNR) using infrared, thermogravimetric analysis, differential scanning calorimetry, gel permeation chromatography, nuclear magnetic resonance 1 H and 13 C methods was studied. The mechanism of thermal degradation of BCNR is proposed. It is shown, that particleboards manufactured using PU-(BCNR) as an adhesive are materials with enhanced flame retardant properties, meeting the requirements of P7 class to EN 312 (especially durable moistureresistant particleboards) and the requirements of the emission class Super E0. The bromine in the structure of the cardanolcontaining polyurethane binder allows achieving both high physical and mechanical characteristics of the particleboards and resistance to flame.
Inverse emulsion copolymerization studies of acrylamide (Am) with methacrylic acid (MAA) are reported. Aqueous monomer solutions were emulsified in toluene with a blend of two surfactants (sorbitan sesquioleate and C18‐terminated acrylamide oligomers). Polymerization kinetics in presence of an oil‐soluble initiator (AIBN) were determined at 40°C as a function of methacrylic acid content and aqueous‐phase pH. Polymerization rates were found to be faster at basic pH than at acidic pH, which appeared to be related to the actual concentration of methacrylic acid in the aqueous phase. Monomer reactivity ratios have been derived as rA‐M = 0.58 ± 0.02 and rM‐A = 4.0 ± 0.10 at pH 4, rA‐M = 0.56 ± 0.005 and rM‐A = 0.15 ± 0.03 at pH 10. These differences were found to have an effect on the molecular characteristics of the copolymers. Initial emulsions and final inverse latexes displayed the same broad size distribution; under basic pH the particle size is relatively insensitive to the ionic comonomer concentration. Poor latex stability is characteristic of copolymer latexes prepared under acidic conditions. Based on these experimental results, some aspects of the polymerization mechanism are discussed.
I n v e r s e emulsion copolymerization s t u d i e s of a c r y l a m i d e (Am) w i t h m e t h a c r y l i c a c i d (MAA) a r e reported. Aqueous monomer emulsions in t o l u e n e were prepared w i t h a blend of two s u r f a c t a n t s ( s o r b i t a n s e s q u i o l e a t e -C18 t e r m i n a t e d acrylamide oligomers). P o l y m e r i z a t i o n k i n e t i c s in presence of an o i l s o l u b l e i n i t i a t o r (AIBN) were determined a t 40°C a s f u n c t i o n of MAA c o n t e n t and aqueous phase pH : monomer r e a c t i v i t y r a t i o s have been d e r i v e d a s rAm = 0.58 0 . 0 2 , rMAA = 4.40 0.10 a t pH 4 and rAm = 0.56 0.005, rMAA = 0.15 0.03 a t pH 10. P a r t i c l e s i z e and s t a b i l i t y of i n v e r s e monomer emulsions and f i n a l l a t e x e s were found t o depend upon t h e aqueous phase pH. a s w e l l a s t h e i n t r i n s i c v i s c o s i t i e s of t h e c o p o l y m e r s ; t h i s s u g g e s t s d i f f e r e n c e s i n p o l y m e r i z a t i o n mechanism v e r s u s t h e pH. I n r e c e n t y e a r s , t h e p r e p a r a t i o n of acrylamide polymers h a s r eceived i n c r e a s i n g i n t e r e s t because of t h e i r use in many p r a c t i c a l a p p l ic a t i o n s ( f l o c c u l a n t s , w a t e r t r e a t m e n t , t e r t i a r y o i l recovery, etc). Among t h e d i f f e r e n t p o l y m e r i z a t i o n p r o c e s s e s which a r e g e n e r a l l y c a r r i e d o u t , i n v e r s e emulsion p o l y m e r i z a t i o n is p a r t i c u l a r l y a t t r a c t i v e , due t o t h e c o l l o i d a l n a t u r e of t h i s t y p e of process, which a s s o c i a t e s a high polymeriz a t i o n r a t e w i t h a high average degree of polymerization. Since t h e pioneer works of VANDERHOFF (1) and KURENKOV ( 2 ) , a few s t u d i e s have been r e p o r t e d concerning t h e i n v e r s e emulsion p o l y m e r i z a t i o n process. I n t h e l a s t y e a r s , much e f f o r t has been focused i n t h i s a r e a , mainly i n t h e c a s e of acrylamide, w i t h t h e purpose of e l u c i d a t i n g t h e polym e r i z a t i o n mechanism (3, 4 , 5, 6). S e v e r a l f e a t u r e s of t h i s r e a c t i o n a r e (*)Current a d d r e s s : ULTI, S i b i r s k i trakt 37, SVERDmSK, G.32 (USSR).
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