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# How do you calculate the % or degree of acrylation of a polymer using integrated NMR peaks?

Hello, I'm trying to use an NMR spectrum to calculate the degree of acrylation for a PLA-PEG-PLA block copolymer that is di-acrylated (one acrylate CH2=CH-COO- group per chain end). I know its supposed to be possible by integrating three peaks in the 5.79-6.43 range associated with the acrylate end groups, compared to a peak at 4.3 that arises from the PEG CH2 groups closest to the PLA blocks. (PEG is [CH2-CH2-O]n with a known n).

However I have a few questions:

1) Why do the acrylate groups gives 3 peaks even though they only contain two types of hydrogens (CH2 and CH)?

2) Is it correct to assume that the combined integration of the acrylate peaks proportionally represent (2H+1H) x 2 end groups = 6H's?

3) Would it be correct, assuming there are two PEG CH2 groups next to PLA blocks, per chain, that the peak at 4.3 proportionally represents 4 H's?

Thank you for any guidance/assistance.

 2 No.1 Revision posted Mar 10 '10 at 08:41 Evgeny Fadeev 577●1

# How do you calculate the % or degree of acrylation of a polymer using integrated NMR peaks?

Hello, I'm trying to use an NMR spectrum to calculate the degree of acrylation for a PLA-PEG-PLA block copolymer that is di-acrylated (one acrylate CH2=CH-COO- group per chain end). I know its supposed to be possible by integrating three peaks in the 5.79-6.43 range associated with the acrylate end groups, compared to a peak at 4.3 that arises from the PEG CH2 groups closest to the PLA blocks. (PEG is [CH2-CH2-O]n with a known n).

However I have a few questions:

1) Why do the acrylate groups gives 3 peaks even though they only contain two types of hydrogens (CH2 and CH)?

2) Is it correct to assume that the combined integration of the acrylate peaks proportionally represent (2H+1H) x 2 end groups = 6H's?

3) Would it be correct, assuming there are two PEG CH2 groups next to PLA blocks, per chain, that the peak at 4.3 proportionally represents 4 H's?

Thank you for any guidance/assistance.

# How do you calculate the % or degree of acrylation of a polymer using integrated NMR peaks?

Hello, I'm trying to use an NMR spectrum to calculate the degree of acrylation define/calculate a "degree of acrylation" for a PLA-PEG-PLA block copolymer that is di-acrylated (one di-acrylated. The macromer or (macro-monomer) is symmetrical in nature (Acr-PLA-PEG-PLA-Acr) and looks like this:

(-CH2-CH-CO-)p-(O-CH[CH3]-CO-)x-(CH2-CH2-O-)m-(O-CH[CH3]-CO-)x-(-CH2-CH-CO)p

For the PEG block in the middle, m is large (I have 4 different samples with pre-defined PEG MWs of 2k, 4k, 8k, and 12k g/mol). For the PLA blocks on either side of the PEG block, I have been able to calculate the average values of x for each sample, using the known value of m for the PEG blocks and the NMR-integrated ratio of PLA CH peaks (at 5.2 ppm) to the main-chain PEG CH2 peaks (at 3.6 ppm). So the formula set-up for that looks like this:

m = (PEG MW) / (EG unit MW)

2x / m = PLA CH peak / PEG CH2 peak

x is typically small (x = 2 - 6 LA units per chain end).

Using two other peaks, I should be able to do something similar to calculate the average value of p and thereby define a "degree of acrylation." So I have two follow-up questions:

4) Since the desire in synthesizing these macromers is to obtain p = 1 (an average of one acrylate CH2=CH-COO- group per chain end). end) then does it make sense if I know its define the "degree of acrylation" as p/1?

5) To calculate p using the NMR peaks: This is supposed to be possible by integrating the three peaks in the 5.79-6.43 range associated with the acrylate end groups, peaks (~ 6ppm) compared to a shifted PEG peak at 4.3 that arises from the represents the PEG CH2 groups closest directly next to the PLA blocks. (PEG is [CH2-CH2-O]n with a known n).

However I have a few questions:

1) Why do the blocks (~ 4.3ppm). Since there are 2 such CH2 groups per chain as well as 2 acrylate groups gives 3 per chain, would the ratio of the two peaks even though they only contain two types of hydrogens (CH2 and CH)?

2) Is it correct to assume that the combined integration of the acrylate peaks proportionally represent (2H+1H) x 2 end groups = 6H's?

3) Would it be correct, assuming there are two PEG directly give me the value of p? For instance, if t refers to the number of CH2 groups per chain located directly next to PLA blocks, per chain, then using a formula similar to that the above:

2p / t = Acr group peaks / shifted PEG CH2 group peak at 4.3 proportionally represents 4 H's?

Thank you for any guidance/assistance.

Since we know t = 2, then I can directly calculate p?

# How do you calculate the % or degree of acrylation of a polymer using integrated NMR peaks?

Hello, I'm trying to use an NMR spectrum to define/calculate a "degree of acrylation" for a PLA-PEG-PLA block copolymer that is di-acrylated. The macromer or (macro-monomer) is symmetrical in nature (Acr-PLA-PEG-PLA-Acr) and looks like this:

(-CH2-CH-CO-)p-(O-CH[CH3]-CO-)x-(CH2-CH2-O-)m-(O-CH[CH3]-CO-)x-(-CH2-CH-CO)p

For the PEG block in the middle, m is large (I have 4 different samples with pre-defined PEG MWs of 2k, 4k, 8k, and 12k g/mol). For the PLA blocks on either side of the PEG block, I have been able to calculate the average values of x for each sample, using the known value of m for the PEG blocks and the NMR-integrated ratio of PLA CH peaks (at 5.2 ppm) to the main-chain PEG CH2 peaks (at 3.6 ppm). So the formula set-up for that looks like this:

m = (PEG MW) / (EG unit MW)

2x / m = PLA CH peak / PEG CH2 peak

x is typically small (x = 2 - 6 LA units per chain end).

Using two other peaks, I should be able to do something similar to calculate the average value of p and thereby define a "degree of acrylation." So I have two follow-up questions:

4) Since the desire in synthesizing these macromers is to obtain p = 1 (an average of one acrylate group per chain end) then does it make sense if I define the "degree of acrylation" as p/1?

5) To calculate p using the NMR peaks: This is supposed to be possible by integrating the three acrylate peaks (~ 6ppm) compared to a shifted PEG peak that represents the PEG CH2 groups directly next to the PLA blocks (~ 4.3ppm). Since there are 2 such CH2 groups per chain as well as 2 acrylate groups per chain, would the ratio of the two peaks directly give me the value of p? For instance, if t refers to the number of CH2 groups per chain located directly next to PLA blocks, then using a formula similar to that above:

2p / t = Acr group peaks / shifted PEG CH2 group peak

Since we know t = 2, then I can directly calculate p?

# How do you calculate the % or degree of acrylation of a polymer using integrated NMR peaks?

Hello, I'm trying to use an NMR spectrum to define/calculate a "degree of acrylation" for a PLA-PEG-PLA block copolymer that is di-acrylated. The macromer or (macro-monomer) is symmetrical in nature (Acr-PLA-PEG-PLA-Acr(Acr)p-(PLA)x-(PEG)m-(PLA)x-(Acr)p) and looks like this:

(-CH2-CH-CO-)p-(O-CH[CH3]-CO-)x-(CH2-CH2-O-)m-(O-CH[CH3]-CO-)x-(-CH2-CH-CO)p

For the PEG block in the middle, m is large (I have 4 different samples with pre-defined PEG MWs of 2k, 4k, 8k, and 12k g/mol). For the PLA blocks on either side of the PEG block, I have been able to calculate the average values of x for each sample, using the known value of m for the PEG blocks and the NMR-integrated ratio of PLA CH peaks (at 5.2 ppm) to the main-chain PEG CH2 peaks (at 3.6 ppm). So the formula set-up for that looks like this:

m = (PEG MW) / (EG unit MW)

2x / m = PLA CH peak / PEG CH2 peak

x is typically small (x = 2 - 6 LA units per chain end).

Using two other peaks, I should be able to do something similar to calculate the average value of p and thereby define a "degree of acrylation." So I have two follow-up questions:

4) Since the desire in synthesizing these macromers is to obtain p = 1 (an average of one acrylate group per chain end) then does it make sense if I just define the "degree of acrylation" as p/1?

5) To calculate p using the NMR peaks: This is supposed to be possible by integrating the three acrylate peaks (~ 6ppm6 ppm) compared to a shifted PEG peak that represents the PEG CH2 groups directly next to the PLA blocks (~ 4.3ppm4.3 ppm). Since there are 2 such CH2 groups per chain as well as 2 acrylate groups per chain, would the ratio of the two peaks directly give me the value of p? For instance, if t refers to the number of CH2 groups per chain located directly next to PLA blocks, then using a formula similar to that above:

2p / t = Acr group peaks / shifted PEG CH2 group peak

Since we know t = 2, then I can directly calculate p?

# How do you calculate the % or degree of acrylation of a polymer using integrated NMR peaks?

Hello, I'm trying to use an NMR spectrum to define/calculate a "degree of acrylation" for a PLA-PEG-PLA block copolymer that is di-acrylated. The macromer or (macro-monomer) is symmetrical in nature ((Acr)p-(PLA)x-(PEG)m-(PLA)x-(Acr)p) and looks like this:

(Acr)p-(PLA)x-(PEG)m-(PLA)x-(Acr)p

OR

(-CH2-CH-CO-)p-(O-CH[CH3]-CO-)x-(CH2-CH2-O-)m-(O-CH[CH3]-CO-)x-(-CH2-CH-CO)p

For the PEG block in the middle, m is large (I have 4 different samples with pre-defined PEG MWs of 2k, 4k, 8k, and 12k g/mol). For the PLA blocks on either side of the PEG block, I have been able to calculate the average values of x for each sample, using the known value of m for the PEG blocks and the NMR-integrated ratio of PLA CH peaks (at 5.2 ppm) to the main-chain PEG CH2 peaks (at 3.6 ppm). So the formula set-up for that looks like this:

m = (PEG MW) / (EG unit MW)

2x / m = PLA CH peak / PEG CH2 peak

x is typically small (x = 2 - 6 LA units per chain end).

Using two other peaks, I should be able to do something similar to calculate the average value of p and thereby define a "degree of acrylation." So I have two follow-up questions:

4) Since the desire in synthesizing these macromers is to obtain p = 1 (an average of one acrylate group per chain end) then does it make sense if I just define the "degree of acrylation" as p/1?

5) To calculate p using the NMR peaks: This is supposed to be possible by integrating the three acrylate peaks (~ 6 ppm) compared to a shifted PEG peak that represents the PEG CH2 groups directly next to the PLA blocks (~ 4.3 ppm). Since there are 2 such CH2 groups per chain as well as 2 acrylate groups per chain, would the ratio of the two peaks directly give me the value of p? For instance, if t refers to the number of CH2 groups per chain located directly next to PLA blocks, then using a formula similar to that above:

2p / t = Acr group peaks / shifted PEG CH2 group peak

Since we know t = 2, then I can directly calculate p?

# How do you calculate the % or degree of acrylation of a polymer using integrated NMR peaks?

Hello, I'm trying to use an NMR spectrum to define/calculate a "degree of acrylation" for a PLA-PEG-PLA block copolymer that is di-acrylated. The macromer or (macro-monomer) is symmetrical in nature (Acr)p-(PLA)x-(PEG)m-(PLA)x-(Acr)p and looks like this:

this: (Acr)p-(PLA)x-(PEG)m-(PLA)x-(Acr)p

OR

(-CH2-CH-CO-)p-(O-CH[CH3]-CO-)x-(CH2-CH2-O-)m-(O-CH[CH3]-CO-)x-(-CH2-CH-CO)p

For the PEG block in the middle, m is large (I have 4 different samples with pre-defined PEG MWs of 2k, 4k, 8k, and 12k g/mol). For the PLA blocks on either side of the PEG block, I have been able to calculate the average values of x for each sample, using the known value of m for the PEG blocks and the NMR-integrated ratio of PLA CH peaks (at 5.2 ppm) to the main-chain PEG CH2 peaks (at 3.6 ppm). So the formula set-up for that looks like this:

m = (PEG MW) / (EG unit MW)

2x / m = PLA CH peak / PEG CH2 peak

x is typically small (x = 2 - 6 LA units per chain end).

Using two other peaks, I should be able to do something similar to calculate the average value of p and thereby define a "degree of acrylation." So I have two follow-up questions:

4) Since the desire in synthesizing these macromers is to obtain p = 1 (an average of one acrylate group per chain end) then does it make sense if I just define the "degree of acrylation" as p/1?

5) To calculate p using the NMR peaks: This is supposed to be possible by integrating the three acrylate peaks (~ 6 ppm) compared to a shifted PEG peak that represents the PEG CH2 groups directly next to the PLA blocks (~ 4.3 ppm). Since there are 2 such CH2 groups per chain as well as 2 acrylate groups per chain, would the ratio of the two peaks directly give me the value of p? For instance, if t refers to the number of CH2 groups per chain located directly next to PLA blocks, then using a formula similar to that above:

2p / t = Acr group peaks / shifted PEG CH2 group peak

Since we know t = 2, then I can directly calculate p?

# How do you calculate the % or degree of acrylation of a polymer using integrated NMR peaks?

Hello, I'm trying to use an NMR spectrum to define/calculate a "degree of acrylation" for a PLA-PEG-PLA block copolymer that is di-acrylated. The macromer or (macro-monomer) is symmetrical in nature and looks like this: (Acr)p-(PLA)x-(PEG)m-(PLA)x-(Acr)p

(-CH2-CH-CO-)p-(O-CH[CH3]-CO-)x-(CH2-CH2-O-)m-(O-CH[CH3]-CO-)x-(-CH2-CH-CO)p

For the PEG block in the middle, m is large (I have 4 different samples with pre-defined PEG MWs of 2k, 4k, 8k, and 12k g/mol). For the PLA blocks on either side of the PEG block, I have been able to calculate the average values of x for each sample, using the known value of m for the PEG blocks and the NMR-integrated ratio of PLA CH peaks (at 5.2 ppm) to the main-chain PEG CH2 peaks (at 3.6 ppm). So the formula set-up for that looks like this:

m = (PEG MW) / (EG unit MW)

2x / m = PLA CH peak / PEG CH2 peak

x is typically small (x = 2 - 6 LA units per chain end).

Using two other peaks, I should be able to do something similar to calculate the average value of p and thereby define a "degree of acrylation." So I have two follow-up questions:

4) Since the desire in synthesizing these macromers is to obtain p = 1 (an average of one acrylate group per chain end) then does it make sense if I just define the "degree of acrylation" as p/1?

5) To calculate p using the NMR peaks: This is supposed to be possible by integrating the three acrylate peaks (~ (~ * 6 ppm) compared to a shifted PEG peak that represents the *PEG CH2 groups directly next to the PLA blocks (~ 4.3 ppm). Since there are 2 such CH2 groups per chain as well as 2 acrylate groups per chain, would the ratio of the two peaks directly give me the value of p? For instance, if t refers to the number of CH2 groups per chain located directly next to PLA blocks, then using a formula similar to that above:

2p / t = Acr group peaks / shifted PEG CH2 group peak

Since we know t = 2, then I can directly calculate p?

# How do you calculate the % or degree of acrylation of a polymer using integrated NMR peaks?

Hello, I'm trying to use an NMR spectrum to define/calculate a "degree of acrylation" for a PLA-PEG-PLA block copolymer that is di-acrylated. The macromer or (macro-monomer) is symmetrical in nature and looks like this:

(Acr)p-(PLA)x-(PEG)m-(PLA)x-(Acr)p

(-CH2-CH-CO-)p-(O-CH[CH3]-CO-)x-(CH2-CH2-O-)m-(O-CH[CH3]-CO-)x-(-CH2-CH-CO)p

For the PEG block in the middle, m is large (I have 4 different samples with pre-defined PEG MWs of 2k, 4k, 8k, and 12k g/mol). For the PLA blocks on either side of the PEG block, I have been able to calculate the average values of x for each sample, using the known value of m for the PEG blocks and the NMR-integrated ratio of PLA CH peaks (at 5.2 ppm) to the main-chain PEG CH2 peaks (at 3.6 ppm). So the formula set-up for that looks like this:

m = (PEG MW) / (EG unit MW)

2x / m = PLA CH peak / PEG CH2 peak

x is typically small (x = 2 - 6 LA units per chain end).

Using two other peaks, I should be able to do something similar to calculate the average value of p and thereby define a "degree of acrylation." So I have two follow-up questions:

4) Since the desire in synthesizing these macromers is to obtain p = 1 (an average of one acrylate group per chain end) then does it make sense if I just define the "degree of acrylation" as p/1?

5) To calculate p using the NMR peaks: This is supposed to be possible by integrating the three acrylate peaks (~ * 6 ppm) compared to a shifted PEG peak that represents the *PEG CH2 groups directly next to the PLA blocks (~ 4.3 ppm). Since there are 2 such CH2 groups per chain as well as 2 acrylate groups per chain, would the ratio of the two peaks directly give me the value of p? For instance, if t refers to the number of CH2 groups per chain located directly next to PLA blocks, then using a formula similar to that above:

2p / t = Acr group peaks / shifted PEG CH2 group peak

Since we know t = 2, then I can directly calculate p?

# How do you calculate the % or degree of acrylation of a polymer using integrated NMR peaks?

Hello, I'm trying to use an NMR spectrum to define/calculate a "degree of acrylation" for a PLA-PEG-PLA block copolymer that is di-acrylated. The macromer or (macro-monomer) is symmetrical in nature and looks like this:

(Acr)p-(PLA)x-(PEG)m-(PLA)x-(Acr)p

(-CH2-CH-CO-)p-(O-CH[CH3]-CO-)x-(CH2-CH2-O-)m-(O-CH[CH3]-CO-)x-(-CH2-CH-CO)p

For the PEG block in the middle, m is large (I have 4 different samples with pre-defined PEG MWs of 2k, 4k, 8k, and 12k g/mol). For the PLA blocks on either side of the PEG block, I have been able to calculate the average values of x for each sample, using the known value of m for the PEG blocks and the NMR-integrated ratio of PLA CH peaks (at 5.2 ppm) to the main-chain PEG CH2 peaks (at 3.6 ppm). So the formula set-up for that looks like this:

m = (PEG MW) / (EG unit MW)

2x / m = PLA CH peak / PEG CH2 peak

x is typically small (x = 2 - 6 LA units per chain end).

Using two other peaks, I should be able to do something similar to calculate the average value of p and thereby define a "degree of acrylation." So I have two follow-up questions:

4) Since the desire in synthesizing these macromers is to obtain p = 1 (an average of one acrylate group per chain end) then does it make sense if I just define the "degree of acrylation" as p/1?

5) To calculate p using the NMR peaks: This is supposed to be possible by integrating the three acrylate peaks (~ * 6 ppm) compared to a shifted PEG peak that represents the *PEG CH2 groups directly next to the PLA blocks (~ 4.3 ppm). Since there are 2 such CH2 groups per chain as well as 2 acrylate groups per chain, would the ratio of the two peaks directly give me the value of p? For instance, if t refers to the number of CH2 groups per chain located directly next to PLA blocks, then using a formula similar to that above:

2p / t = Acr group peaks / shifted PEG CH2 group peak

Since we know t = 2, then I can directly calculate p?

# How do you calculate the % or degree of acrylation of a polymer using integrated NMR peaks?

Hello, I'm trying to use an NMR spectrum to define/calculate a "degree of acrylation" for a PLA-PEG-PLA block copolymer that is di-acrylated. The macromer or (macro-monomer) is symmetrical in nature and looks like this:

(Acr)p-(PLA)x-(PEG)m-(PLA)x-(Acr)p

(-CH2-CH-CO-)p-(O-CH[CH3]-CO-)x-(CH2-CH2-O-)m-(O-CH[CH3]-CO-)x-(-CH2-CH-CO)p

For the PEG block in the middle, m is large (I have 4 different samples with pre-defined PEG MWs of 2k, 4k, 8k, and 12k g/mol). For the PLA blocks on either side of the PEG block, I have been able to calculate the average values of x for each sample, using the known value of m for the PEG blocks and the NMR-integrated ratio of PLA CH peaks (at 5.2 ppm) to the main-chain PEG CH2 peaks (at 3.6 ppm). So the formula set-up for that looks like this:

m = (PEG MW) / (EG unit MW)

2x / m = PLA CH peak / PEG CH2 peak

x is typically small (x = 2 - 6 LA units per chain end).

Using two other peaks, In order to calculate the average value of p and thereby define a "degree of acrylation," I should be able to do something use a similar to calculate the average value of p and thereby define a "degree of acrylation." So process. Presumably, by integrating the three acrylate peaks (~ 6 ppm) compared to a shifted PEG peak that represents the PEG CH2 groups directly next to the PLA blocks (~ 4.3 ppm). However, I have a few questions:

1) Why do the acrylate groups gives 3 peaks even though they only contain two follow-up questions:types of hydrogens (CH2 and CH)?

2) Is it correct to assume that the combined integration of the acrylate peaks proportionally represent (2H+1H) x 2 end groups = 6H's?

3) Would it be correct, assuming there are two PEG CH2 groups next to PLA blocks, per chain, that the peak at 4.3 proportionally represents 4 H's?

4) Since the desire in synthesizing these macromers is to obtain p = 1 (an average of one acrylate group per chain end) then does it make sense if I just define the "degree of acrylation" as p/1?

5) To calculate p using the NMR peaks: This is supposed to be possible by integrating the three acrylate peaks (~ 6 ppm) compared to a shifted PEG peak that represents the PEG CH2 groups directly next to the PLA blocks (~ 4.3 ppm). Since there are 2 such CH2 groups per chain as well as 2 acrylate groups per chain, would the ratio of the two peaks directly give me the value of p? For instance, if t refers to the number of CH2 groups per chain located directly next to PLA blocks, then using a formula similar to that above:

2p / t = Acr group peaks / shifted PEG CH2 group peak

Since we know t = 2, then I can directly calculate p?

# How do you calculate the % or degree of acrylation of a polymer using integrated NMR peaks?

Hello, I'm trying to use an NMR spectrum to define/calculate a "degree of acrylation" for a PLA-PEG-PLA block copolymer that is di-acrylated. The macromer or (macro-monomer) is symmetrical in nature and looks like this:

(Acr)p-(PLA)x-(PEG)m-(PLA)x-(Acr)p

(-CH2-CH-CO-)p-(O-CH[CH3]-CO-)x-(CH2-CH2-O-)m-(O-CH[CH3]-CO-)x-(-CH2-CH-CO)p

For the PEG block in the middle, m is large (I have 4 different samples with pre-defined PEG MWs of 2k, 4k, 8k, and 12k g/mol). For the PLA blocks on either side of the PEG block, I have been able to calculate the average values of x for each sample, using the known value of m for the PEG blocks and the NMR-integrated ratio of PLA CH peaks (at 5.2 ppm) to the main-chain PEG CH2 peaks (at 3.6 ppm). So the formula set-up for that looks like this:

m = (PEG MW) / (EG unit MW)

2x / m = PLA CH peak / PEG CH2 peak

x is typically small (x = 2 - 6 LA units per chain end).

In order to calculate the average value of p and thereby define a "degree of acrylation," I should be able to use a similar process. Presumably, by integrating the three acrylate group peaks (~ 6 ppm) compared to a shifted PEG peak that represents the PEG CH2 groups directly next to the PLA blocks (~ 4.3 ppm). However, I have a few questions:

1) Why do the acrylate groups gives 3 peaks even though they only contain two types of hydrogens (CH2 and CH)?

2) Is it correct to assume that the combined integration of the acrylate peaks proportionally represent (2H+1H) x 2 end groups = 6H's?

3) Would it be correct, assuming there are two PEG CH2 groups next to PLA blocks, per chain, that the peak at 4.3 proportionally represents 4 H's?

4) Since the desire in synthesizing these macromers is to obtain p = 1 (an average of one acrylate group per chain end) then does it make sense if I just define the "degree of acrylation" as p/1?

5) To calculate p using the NMR peaks: This is supposed to be possible by integrating the three acrylate peaks (~ 6 ppm) compared to a shifted PEG peak that represents the PEG CH2 groups directly next to the PLA blocks (~ 4.3 ppm). Since there are 2 such CH2 groups per chain as well as 2 acrylate groups per chain, would the ratio of the two peaks directly give me the value of p? For instance, if t refers to the number of CH2 groups per chain located directly next to PLA blocks, then using a formula similar to that above:

2p / t = Acr group peaks / shifted PEG CH2 group peak

Since we know t = 2, then I can directly calculate p?