<MultiModal>![This image describes a polymer, whose structure can be described as: The polymer has a branched chain, with structures [X]CC(CO[Z])O[Y] and [M]CCO[M]C, with degrees of polymerization of n and m, respectively, where X, Y, M, and Z all represent the linking sites of the polymer monomer, M is connected to M to form the branched chain repeating unit, and [M] is connected to [Z] of the main chain; the end-capping structures are C=CC(C)(C)O[X] and [Y]CC=C, where X and Y represent the linking sites, corresponding to X and Y of the monomer.](/media/uploads/b741889f-7152-4b8d-848c-08f076f9de27.png)</MultiModal>

The polymer in the above figure is named $\rm PEO^B$, and its synthesis method is as follows: Under nitrogen protection and in the presence of the crown ether $\rm 18-C-6$, the ring-opening polymerization of $\bf B$ is initiated by the potassium alkoxide initiator $\bf A$, and then the bromide $\bf C$ is added for end-capping.

The researchers determined the degree of polymerization of the polymer by MALDI-TOF mass spectrometry, determined its mass-to-charge ratio after $\rm PEO^B$ was combined with a sodium ion, and the obtained mass spectrum image is shown below, where the horizontal coordinate represents the mass-to-charge ratio m/z of $\rm [PEO^B-Na]^+$:

<MultiModal>![This image is a mass spectrum, the horizontal coordinate in the image is the mass-to-charge ratio m/z, the image has 15 peaks, the spacing between each peak is the same, the peak height is approximately normally distributed, the most central peak is the highest peak, the corresponding horizontal coordinate is about 2800, and the horizontal coordinates corresponding to the leftmost and rightmost lowest peaks are about 1250 and 4350,](/media/uploads/4599004c-2459-45b0-b07b-780d3d0515ec.png)</MultiModal>

The polymer $\rm PEO^B$ and a substance $\rm POSS$ containing a thiol structure are mixed in a certain proportion and dissolved in tetrahydrofuran, a lithium salt electrolyte and a small amount of photoinitiator are added, dropped on the surface of a lithium metal plate, the reaction is initiated by ultraviolet light, and the solvent is removed by vacuum drying to obtain a solid polymer electrolyte membrane with a cross-linked structure and good deformability.

According to the above information, which of the following statements is correct:
<MultiModal>![该图片描述了一个高分子，其结构可描述为：该高分子是具有一个支链，结构为[X]CC(CO[Z])O[Y]和[M]CCO[M]C，聚合度分别为n和m，其中X,Y,M,Z均表示聚合物单体的链接位点，M与M相连构成支链重复单元，同时[M]与主链的[Z]相连；封端的结构为C=CC(C)(C)O[X]和[Y]CC=C，其中X,Y表示连接位点，与单体的X,Y相对应。](/media/uploads/b741889f-7152-4b8d-848c-08f076f9de27.png)</MultiModal>

上图的高分子名为$\rm PEO^B$，其合成方法如下：在氮气保护和冠醚$\rm 18-C-6$存在下，由醇钾引发剂$\bf A$引发$\bf B$的开环聚合，之后加入溴化物$\bf C$封端。

实验人员通过MALDI-TOF质谱测定该高分子的聚合度，使$\rm PEO^B$与一个钠离子结合后测定其质荷比，得到的质谱图像如下图，其中横坐标表示$\rm [PEO^B-Na]^+$的质荷比m/z：

<MultiModal>![本图为质谱图，图片中横坐标为质荷比m/z，图像具有15个峰，每个峰之间的间距相同，峰高约呈正态分布，最中心的峰位为最高峰，对应的横坐标约为2800，最左右两个最低峰对应的横坐标约为1250和4350，](/media/uploads/4599004c-2459-45b0-b07b-780d3d0515ec.png)</MultiModal>

该高分子$\rm PEO^B$与某含有硫醇结构的物质$\rm POSS$以一定比例混合溶于四氢呋喃，加入锂盐电解质和少量光引发剂，滴在锂金属板表面，用紫外光引发反应，真空干燥去除溶剂，得到具有交联结构和较好变形性的固体高分子电解膜。

根据以上信息，下列说法正确的是：
All other options are incorrect
m = 2
The highest peak in the mass spectrum corresponds to a degree of polymerization n = 12
The difference between the relative molecular mass of $\bf A$ and the relative molecular mass of $\bf C$ is less than 2.
The mixing ratio of $\rm PEO^B$ and $\rm POSS$ is approximately 1:1
其他选项均不正确
m = 2
质谱图中最高的峰对应的聚合度n = 12
$\bf A$的相对分子质量减去$\bf C$的相对分子质量的差值小于2
$\rm PEO^B$和$\rm POSS$的混合比例约为1：1
Based on the polymer synthesis pathway and polymer structure, the structure of potassium alkoxide $\bf A$ is obviously an end-group structure, C=CC(C)(C)O[K]. Since it induces ring-opening polymerization, $\bf B$ obviously has an ethylene oxide structure, so the structure of $\bf B$ is [M]CCOC, the degree of polymerization is m, and the capping structure connected to the M site is [M]OCC1CO1. The bromide $\bf C$ used for end-capping has the structure C=CCBr. According to the chemical formula, option D is incorrect.

<Checkpoint>[The structure of potassium alkoxide $\bf A$ is C=CC(C)(C)O[K]](1)</Checkpoint>

<Checkpoint>[The structure of $\bf B$ is [M]CCOC, the degree of polymerization is m, and the capping structure connected to the M site is [M]OCC1CO1](1)</Checkpoint>

<Checkpoint>[The structure of $\bf C$ is C=CCBr](1)</Checkpoint>

Observing the mass spectrum image, the abscissa of the last peak in the figure differs from the first peak by 3100, a difference of 14 intervals; therefore, it can be determined that the relative molecular mass of monomer $\bf B$ is $\rm 3100/14\approx221$; according to the structure of $\bf B$, it can be deduced that $\rm m = 3$.

<Checkpoint>[The relative molecular mass of monomer $\bf B$ is $\rm 3100/14\approx221$](1)</Checkpoint>

<Checkpoint>[$\rm m = 3$](1)</Checkpoint>

The m/z corresponding to the highest peak is approximately 2800, corresponding to the highest degree of polymerization n, and the end groups are $\rm C_5H_9O, C_3H_4$; therefore, it is calculated that $\rm n=(2800-85-40)/221\approx12$

<Checkpoint>[The degree of polymerization $\rm n = 12$ corresponding to the highest peak in the mass spectrum](1)</Checkpoint>

The reaction between $\rm PEO^B$ and $\rm POSS$ should be a free radical polymerization reaction between thiol and double bond. To form a cross-linked system, the mixing ratio should be 2:1, and option E is incorrect.

<Checkpoint>[The reaction between $\rm PEO^B$ and $\rm POSS$ should be a free radical polymerization reaction between thiol and double bond](1)</Checkpoint>

<Checkpoint>[The mixing ratio of $\rm PEO^B$ and $\rm POSS$ should be 2:1](1)</Checkpoint>

<MultiModal>![The structure of potassium alkoxide $\bf A$ is C=CC(C)(C)O[K]; The structure of $\bf B$ is [M]CCOC, the degree of polymerization is m, and the capping structure connected to the M site is [M]OCC1CO1; The structure of $\bf C$ is C=CCBr](/media/uploads/d5d4e6fd-eefb-4b65-af60-12fb98e40027.png)</MultiModal>
根据高分子合成路径和高分子结构可知，醇钾$\bf A$的结构很明显为端基结构，C=CC(C)(C)O[K]。由于诱发开环聚合，因此$\bf B$很明显存在环氧乙烷结构，因此$\bf B$结构为[M]CCOC，聚合度为m，与M位点连接的封端结构为[M]OCC1CO1。用于封端的溴化物$\bf C$结构为C=CCBr，根据化学式可知选项D错误。

<Checkpoint>[醇钾$\bf A$的结构为C=CC(C)(C)O[K]](1)</Checkpoint>

<Checkpoint>[$\bf B$结构为[M]CCOC，聚合度为m，与M位点连接的封端结构为[M]OCC1CO1](1)</Checkpoint>

<Checkpoint>[$\bf C$结构为C=CCBr](1)</Checkpoint>

观察质谱图像，图中最后一个峰与第一个峰的横坐标相差3100，相差14个间距；因此可判断单体$\bf B$的相对分子量为$\rm 3100/14\approx221$；根据$\bf B$的结构可推算得到$\rm m = 3$。

<Checkpoint>[单体$\bf B$的相对分子量为$\rm 3100/14\approx221$](1)</Checkpoint>

<Checkpoint>[$\rm m = 3$](1)</Checkpoint>

最高峰对应的m/z约为2800，对应最高聚合度n，端基分别为$\rm C_5H_9O, C_3H_4$; 故计算得$\rm n=(2800-85-40)/221\approx12$

<Checkpoint>[质谱图中最高的峰对应的聚合度$\rm n = 12$](1)</Checkpoint>

$\rm PEO^B$和$\rm POSS$的反应应当为巯基与双键的自由基聚合反应，为形成交联体系，混合比例应当为2：1，选项E错误。

<Checkpoint>[$\rm PEO^B$和$\rm POSS$的反应应当为巯基与双键的自由基聚合反应](1)</Checkpoint>

<Checkpoint>[$\rm PEO^B$和$\rm POSS$混合比例应当为2：1](1)</Checkpoint>

<MultiModal>![醇钾$\bf A$的结构为C=CC(C)(C)O[K]; $\bf B$结构为[M]CCOC，聚合度为m，与M位点连接的封端结构为[M]OCC1CO1; $\bf C$结构为C=CCBr](/media/uploads/d5d4e6fd-eefb-4b65-af60-12fb98e40027.png)</MultiModal>