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có thể hiểu được 1 số tính chất, đặc điểm cơ bản của copolymer từ đó ứng dụng vào polymerzation.Ngoài ra còn có thêm 1 số tài liệu khác liên quan đến vấn đề này mà bạn có thể dễ dàng tìm kiếm ở các trang mạng khác.
Copolymer Classification by Monomer Composition Copolymer Homopolymer Block Graft Alternating Homopolymer Consist of only one type of constitutional repeating unit (A) AAAAAAAAAAAAAAA copolymer Consists of two or more constitutional repeating units (A.B ) Statistical Alternating copolymer Shown is an alternating copolymer in which each of the ‘mers’ alternates in an ordered fashion Statistical copolymer (Random) When one type of ‘mer’ alternates with no specific pattern, the arrangement is known as a random copolymer Alternating and random copolymers with the same ‘mers’ can have very different properties Copolymers – Graft Copolymer When ‘sections’ of one type of polymer is attached or ‘grafted’ to the main chain of another polymer Copolymers – Block Copolymer When small groups of monomers are attached to each other in alternating fashion, the product is called a block copolymer Terpolymer When there are three types of ‘mers’ polymerized together it is known as a terpolymer Acrylonitrile Butadiene Styrene (ABS) is a terpolymer of Acrylic, Butadiene rubber, and Styrene This gives the Acrylic and Styrene added impact resistance and the properties can be manipulated by changing the amount of each of the individual ‘mers’ Các phương pháp tổng hợp copolyme? Đồng trùng hợp gốc tự Điều kiện phản ứng Copolymerization Kinetics M1 M1 + + M1 M2 k11 k12 M1M1 Homo-propagation M1M2 Cross-propagation Terminal Model • • • • Copolymerization Examples r1 = r2 = 1.0 r1 = r2 = 0.0 r1 and r2 between and 1.0 r1 >> 1.0 and r2 1.0 and r2 < 1.0 1.0 D 0.8 – r1 >> 1.0 >> r2 Significant drift in feed ratio F1 0.6 A 0.2 0.0 B C 0.4 0.0 0.2 0.4 f1 0.6 0.8 1.0 r1 = r2 >> • r1 = k12 = • r2 = k21 = • Chuỗi copolyme kết thúc tâm hoạt động M1 cộng M1 • Chuỗi copolyme kết thúc tâm hoạt động M2 cộng M2 • Tạo homopolyme, sản phẩm hỗn hợp polyme Composition drift • Các thành phần hỗn hợp monome thay đổi với độ chuyển hóa ngày tăng, thành phần chuỗi polymer • Khi xác định r, độ chuyển hóa thấp, vào cuối thí nghiệm, tỷ lệ nồng độ monomer giống lúc đầu • Tuy nhiên, muốn độ chuyển hóa cao, thành phần mong muốn copolyme đạt cách thêm monomer phản ứng mạnh cách tính toán r1 & r ? Experimental Determination of r1 & r2 Mayo and Lewis rearrange copolymer eq and can get [ M ] d [ M ] r1[ M ] r2 1 1 [ M ] d [ M ] [ M ] monomer comp [M ] [M ] d[M1 ] d[M ] then vary r1 value (put) and again r r1 copolymer comp experiment experiment experiment Experimental Determination of r1 & r2 Finemann and Ross Recall F1 r1 f1 f1 f 2 r1 f1 f1 f r2 f 2 f 1(1 F 1) f ( F 1) r2 1 r1 F1 (1 f1 ) F1 (1 f1 ) A const B const at low conversion r1 A r2 B Slope : r1 Intersection : r2 Structure and Reactivity @ Q-e scheme of Alfred Price As know r, prediction is possible to polar, resonance effect Guidance to chemists k ij Pi Q j exp( e i e j ) where P : hoạt tính tâm hoạt động (active center reactivity) Q : hoạt tính monome (monomer reactivity) e1 and e2 are the polarity of the radical M1• and M2 • respectively ri k ii P Q exp(ei ei ) i i k ij Pi Q j exp(ei e j ) ri Qi exp[ e i (e i e j )] Qj Q – e scheme St AN MA MMA VAc P e Q 58.23 21.03 2.413 751.3 -0.8 1.233 0.577 0.397 -0.027 0.4 0.42 0.24 0.024 Effect of Reaction Condition Reaction medium Depend on Solubility, PH, Viscosity, and Polarity Temperature k 11 A 11 ( E 12 E 11 ) exp[ ] k 12 A 12 RT But the effect of temperature on r is not large r1 Pressure d ln r1 (df1V11 V12 ) dP RT But the effect of pressure on r is not large Reactivity @ Substituent Effects Φ, CH2=CH- > -C≡N, -COR > -COOH, -COOR > -Cl > -O-COR, -R > -OR, -H monomers increase relative reactivity by resonance stabilization The resonance stability of the monomer increases the reactivity of the monomer The resonance stability of the radical is weakened reactivity of the radical Effect of Reaction Condition Structure and Reactivity I Resonance Stabilization II Polar Effects III Steric Effects I.Resonance Stabilization Substituent on Double Bond -H, -OCH3 Relative Reactivity of Monomer -OAc, -CH3 1.5-5 -COO, -COOH 20-60 -C2H3, -C6H5 50-100 -Cl -CN, -COR 3-20 30-60 Table 6-4 Rate Constant(k12) for Radical-Monomer Reactions Monomer(M1) Butadiene Styrene Methyl _methacrylate Acrylonitrile Methyl _acrylate Vinyl chloride Vinyl acetate Polymer Radical Buta- StyMethyl Acryl diene ren Metacrylate oe nirile 100 70 280 165 2,060 1,130 130 330 314 413 515 422 130 11 215 9.7 3.4 268 52 26 98,00 49,00 13,10 1,960 1,310 720 230 Methyl Vinyl Vinyl Acrylat Acetat Chlorid e e e 41,800 10,045 4,180 2,510 2,090 520 530 230,00 154,00 319,00 550,00 110,000 46,000 225,00 23,000 187,00 0,100 2,300 11,000 6,490 Q1 e1 2.39 1.00 0.74 0.60 0.42 0.04 0.02 1.05 0.80 0.40 1.20 0.60 0.20 0.22 ... the arrangement is known as a random copolymer Alternating and random copolymers with the same ‘mers’ can have very different properties Copolymers – Graft Copolymer When ‘sections’ of one type... (A.B ) Statistical Alternating copolymer Shown is an alternating copolymer in which each of the ‘mers’ alternates in an ordered fashion Statistical copolymer (Random) When one type of ‘mer’ alternates... Composition Copolymer Homopolymer Block Graft Alternating Homopolymer Consist of only one type of constitutional repeating unit (A) AAAAAAAAAAAAAAA copolymer Consists of two or more constitutional